JEPARTMENT  OF  THE  INTERIOR 
GENERAL  LAND  OFFICE 


T  A 


ADVANCE  SHEETS 

of  Chapters  I  to  VI,  inclusive,  of  a 
revision  of  the 


MANUAL  OF  INSTRUCTIONS 

FOR  THE 

SURVEY  OF  THE  PUBLIC  LAND^ 
OF  THE  UNITED  STATES 


Prepared  and  published  under   the  direction 
of  the  Commissioner  of  the  General  Land  Office 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1919 


GIFT   OF 


DEPARTMENT  OF  THE  INTERIOR 

GENERAL  LAND  OFFICE 


ADVANCE  SHEETS 

of  Chapters  I  to  VI,  inclusive,  of  a 
revision  of  the 

MANUAL  OF  INSTRUCTIONS 

FOR  THE 

SURVEY  OF  THE  PUBLIC  LANDS 
OF  THE  UNITED  STATES 


Prepared  and  published  cinder  the  direction 
of  the  Commissioner  of  the  General  Land  Office 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1919 


3HT  r 


DEPARTMENT    OF    THE    INTERIOR 

GENERAL    LAND    OFFICE 

WASHINGTON,  June  16,  1919. 

GENTLEMEN:  It  has  been  deemed  advisable  to  publish  advance 
sheets  of  six  chapters  of  a  new  edition  of  the  Manual  of  Surveying 
Instructions,  as  follows:  (I)  Regulations  Imposed  by  Law;  (II) 
Instruments  and  Methods;  (III)  System  of  Rectangular  Surveys; 
(IV)  Corner  Monuments;  (V)  Restoration  of  Lost  Corners;  and, 
(VI)  Resurveys.  These  advance  sheets  will  immediately  supersede 
the  related  provisions  of  the  Manual  of  1902,  except  as  may  be  found 
impracticable  in  the  case  of  surveys  already  in  process  of  execution, 
or  in  the  instance  of  returns  of  surveys  now  in  course  of  preparation, 
otherwise  the  provisions  of  the  Manual  of  1902  will  remain  in  full  force 
and  effect. 

Every  member  of  the  surveying  service  is  requested  to  report  to 
the  undersigned  any  typographical  errors  which  may  be  detected, 
to  the  end  that  the  same  may  be  removed  from  the  completed 
edition. 

Very  respectfully, 

CLAY  TALLMAN, 

Commissioner. 

To  the  SURVEYING  SERVICE  OF  THE  GENERAL  LAND  OFFICE. 


CONTENTS. 


CHAPTER  I. 


REGULATIONS  IMPOSED  BY  LAW.  Page. 

The  Public  Domain 1 

lews  Relating  to  Surveys 5 

General  Rules 18 

The  Manual 19 

The  Standard  Field  Tables 20 

Ephemeris  of  the  Sun  and  Polaris,  and  Tables  of  A  zimuths  of  Polaris 21 

CHAPTER   II. 

INSTRUMENTS  AND  METHODS. 

Measurements 23 

The  long  steel  tape 24 

Stadia  measurements 29 

Triangulations 35 

Instruments  and  requirements  as  to  their  adjustment 39 

General  statement,  time,  latitude  and  azimuth 42 

Analytical  notation,  declination  and  refraction 43 

Time 51 

Time  in  its  relation  to  Polaris  observations 53 

Altitude  observation  of  the  sun  for  apparent  time 62 

Meridian  observation  of  the  sun  for  apparent  noon 64 

Time  from  the  solar  attachment 66 

Latitude 66 

Meridian  altitude  observation  of  the  sun  for  latitude 60 

Altitude  observation  of  Polaris  for  latitude 69 

Azimuth 71 

The  solar  attachment 71 

Description. 72 

Adjustment 75 

U  so 80 

Test 82 

The  solar  compass 83 

Errors  in  azimuth,  due  to  small  errors  in  declination  or  latitude 85 

Polaris  at  elongation 86 

Azimuth  of  Polaris  at  an}'  hour  angle ; 93 

Polaris  at  sunset  or  sunrise 100 

Altitude  observation  of  the  sun  for  azimuth 102 

Equal  altitude  observations  of  the  sun  for  meridian  .'. 114 

The  true  parallel  of  latitude 121 

Solar  method. 122 

Tangent  method 122 

Secant  method 124 

Convergency  of  meridians 12t> 

Lengths  of  arcs  of  the  earth's  surface 128 


VI  M  AN  UAL  OF  S  I"  X  \  J :  Y I A  G  IN  STKUC  TION  S. 

CHAPTER  III. 

SYSTEM  OF  RECTANGULAR  SURVEYS.  Page. 

General  scheme 131 

Initial  points 132 

Principal  meridian '.  • 133 

Meridians  and  base  lines  of  the  United  States  Rectangular  Surveys 134 

Base  line 135 

Standard  parallels 136 

Guide  meridians 137 

Township  exteriors 138 

Regular  order 138 

Irregular  order  and  partial  surveys 143 

General  exceptions 143 

Completion  of  partially  surveyed  exteriors 148 

Retraccments  before  subdividing 150 

Rectangular  limits 150 

Rectification  of  defective  exteriors  before  subdividing  and  method  o£  es- 
tablishing  new  governing  boundaries  where  the  previously  surveyed  ex- 
teriors are  found  to  be  defective 152 

Tables  of  latitudes  and  departures  and  closing  errors 159 

Subdivision  of  townships 160 

Regular  boundaries 160 

Irregular  boundaries 166 

Sectional  guide  meridian 166 

Sectional  correction  line . .  166 

Closing  section  lines , , . ....  170 

Subdivision  of  sections -  173 

Subdivision  by  protraction 175 

Subdivision  by  survey 180 

Fragmentary  subdivision  of  townships , .  184 

Fractional  townships .- 184 

Retracements ,.  •  188 

Completion  of  partially  surveyed  sections 190 

Subdivision  of  fractional  sections  resulting  from  fragmentary  surveys.,. . .  205 
Completing  the  subdivision  of  a  partial  township  resulting  from  fragmen- 
tary surveys •; . .  209 

Meandering 212 

Rivers 215 

Lakes 216 

Islands 217 

Limits  of  closure 218 

Marking  lines  between  corners 219 

Summary  of  objects  to  be  noted,  and  sketches ;  221 

CHAPTER  IV. 
CORNER  MONUMENTS. 

The  legal  significance  of  a  corner  monument 227 

Corner  material .....:  229 

Witness  corners 230 


CONTENTS.  VH 

Page. 

Marking  corners 231 

Marks  on  iron  post  monuments 232 

Marks  on  stone  monuments 240 

Marks  on  tree  monuments 244 

Corner  accessories 249 

Bearing  trees,  bearing  objects,  and  memorials 250 

Mound  of  stone 251 

Pits 252 

Arrangement  and  marking  of  corner  accessories 252 

CHAPTER  V. 
RESTORATION  OF  LOST  CORNERS. 

Identification  of  existent  corners 259 

Restoration  of  lost  corners 263 

Primary  methods 265 

(a)  Double  proportionate  measurement 265 

(ft)  Single  proportionate  measurement 268 

(c)  Closing  comers 269 

Secondary  methods 270 

(d )  Broken  boundaries 270 

(«)  Original  control 271 

(/)  Index  correction  for  average  error  in  alinement  and  measurement .  271 

Special  cases 271 

(<7)  Miscellaneous  control 272 

CHAPTER  VI. 

RESURVEYS. 

Jurisdiction 275 

Limit  of  authority  of  surveyor 276 

Bona  fide  rights  of  claimants 277 

General  field  methods 280 

The  Dependent  Resurvey , 282 

General  control • 282 

Reestablishment  of  true  lines 287 

Additional  methods  for  the  protection  of  bona  fide  rights 239 

Example v 289 

The  Independent  Resurvey 294 

Reestablishment  of  outboundaries 295 

Metes-and-bounds  survey  of  private  claims 296 

The  projection  of  new  lines 303 

Additional  chapter  subjects  to  be  included  in  a  mbsequent  edition  of  the  completed  Manual. 
VTI.  Special  surveys  and  instructions. 
VIII.  Field  notes. 
IX.  Plats. 
X.  Mineral  surveys. 


CHAPTER  I. 

REGULATIONS  IMPOSED  BY  LAW. 

THE  PUBLIC  DOMAIN. 

1.  The  survey  of  the  public  lands  of  the  United  States  is  insep- 
arably associated  with  questions  relating  to  the  acquisition  and  dis- 
posal of  proprietary  title  to  the  lands  which  have  been  added  to  the 
area  included  in  the  original  thirteen  States.  The  term  "public 
domain"  has  been  applied  broadly  to  the  entire  aforementioned 
area  in  so  far  as  the  lands  have  been  subject  to  survey  and  disposal 
by  the  United  States,  and  of  interest  herein  may  be  mentioned  the 
twenty-nine  States  and  the  District  of  Alaska  surveyed  or  in  progress 
of  survey  under  the  United  States  rectangular  system,  as  follows: 

Alabama. — Included  in  the  territory  of  the  original  thirteen 
States,  and  admitted  into  the  Union  December  14,  1819  (3  Stat.? 
608) ;  surveys  practically  completed  and  original  records  transferred 
to  the  Secretary  of  State  at  Montgomery. 

Arizona. — Included  in  the  lands  ceded  by  Mexico,  in  1848,  and 
the  Gadsden  purchase,  in  1853,  and  admitted  into  the  Union  Feb- 
ruary 14,  1912  (36  Stat.,  557  and  37  Stat.,  1728);  surveys  in  progress; 
United  States  Surveyor  General  at  Phoenix. 

Arkansas. — Acquired  under  the  Louisiana  Purchase,  in  1803,  and 
admitted  into  the  Union  June  15,  1836  (5  Stat.,  50);  surveys  practi- 
cally completed  and  original  records  transferred  to  the  Commissioner 
of  State  Lands  at  Little  Rock. 

California. — Ceded  by  Mexico,  in  1848,  and  admitted  into  the 
Union  September  9,  1850  (9  Stat.,  452);  surveys  in  progress;  United 
States  Surveyor  General  at  San  Francisco. 

Colorado. — Acquired  largely  under  the  Louisiana  Purchase,  in 
1803,  but  including  additional  land,  title  to  which  was  quieted 
through  treaty  with  Spain,  in  1819,  with  other  lands  annexed  with 
Texas,  in  1845,  and  lands  ceded  by  Mexico,  in  1848,  and  admitted  into 
the  Union  August  1,  1876  (18  Stat.,  474,  and  19  Stat.,  665);  surveys 
in  progress;  United  States  Surveyor  General  at  Denver. 

Florida. — Ceded  by  Spain  in  1819,  and  admitted  into  the  Union 
March  3,  1845  (5  Stat.,  742);  surveys  practically  completed  and 
original  records  transferred  to  the  CommiBsioner  of  Agriculture  at 
Tallahassee. 


2  MAM  AL  OF  SLKVi,riNG    INSTRUCTIONS. 

Idaht. — Acquired  with  the  Oregon  Territory,  title  to  which,  was 
established  in  1846,  and  admitted  into  the  Union  July  3,  1890  (26 
Stat.,  215);  surveys  in  progress;  United  States  Surveyor  General  at 
Boise. 

Illinois. — Included  in  the  territory  of  the  original  thirteen  States 
and  admitted  into  the  Union  December  3,  1818  (3  Stat.,  536);  sur- 
veys practically  completed  and  original  records  transferred  to  the 
Auditor  of  State  at  Springfield. 

Indiana. — Included  in  the  territory  of  the  original  thirteen  States 
and  admitted  into  the  Union  December  11,  1816  (3  Stat.,  399);  sur- 
veys practically  completed  and  original  records  transferred  to  the 
Auditor  of  State  at  Indianapolis. 

Iowa. — Acquired  under  the  Louisiana  Purchase,  in  1803,  and  ad- 
mitted into  the  Union  December  28,  1846  (9  Stat.,  117);  surveys 
practically  completed  and  original  records  transferred  to  the  Sec- 
retary of  State  at  Des  Moines. 

Kansas. — Acquired  under  the  Louisiana  Purchase,  in  1803,  and 
with  lands  annexed  with  Texas,  in  1845,  and  admitted  into  the 
Union  January  29,  1861  (12  Stat.,  126);  surveys  practically  com- 
pleted and  original  records  transferred  to  the  Auditor  of  State  and 
Register  of  State  Lands  at  Topeka. 

Louisiana. — Included  in  the  Louisiana  Purchase,  in  1803,  and 
boundary  extended  to  include  additional  lands,  title  to  which  was 
quieted  through  treaty  with  Spain  in  1819,  and  admitted  into  the 
Union  April  30,  1812  (2  Stat.,  701);  surveys  practically  completed 
and  original  records  transferred  to  the  Register  of  State  Lands  at 
Baton  Rouge. 

Michigan.—  Included  in  the  territory  of  the  original  thirteen 
States  and  admitted  into  the  Union  January  26,  1837  (5  Stat.,  144); 
surveys  practically  completed  and  original  records  transferred  to  the 
Commissioner  of  State  Land  Office  at  Lansing. 

Minnesota. — Included  in  the  territory  of  the  original  thirteen 
States,  and  with  lands  acquired  under  the  Louisiana  Purchase,  in 
1803,  and  admitted  into  the  Union  May  11,  1858  (11  Stat.,  285); 
surveys  practically  completed  and  original  records  transferred  to 
the  Secretary  of  State  at  St.  Paul. 

Mississippi. — Included  in  the  territory  of  the  original  thirteen 
States  and  admitted  into  the  Union  December  10,  1817  (3  Stat., 
472);  surveys  practically  completed  and  original  records  transferred 
to  the  Commissioner  of  State  Lands  at  Jackson. 


REGULATIONS  IMPOSED  BY  LAW.  3 

Missouri. — Acquired  under  the  Louisiana  Purchase,  in  1803,  and 
admitted  into  the  Union  August  10,  1821  (3  Stat.,  645,  and  3  Stat,, 
Appendix  II);  surveys  practically  completed  and  original  records 
transferred  to  the  Secretary  of  State  at  Jefferson  City. 

Montana. — Acquired  under  the  Louisiana  Purchase,  in  1803,  and 
with  the  Oregon  Territory,  title  to  which  was  established  in  1846, 
and  admitted  into  the  Union  November  8,  1889  (25  Stat.,  676,  and 
26  Stat.,  1551);  surveys  in  progress;  United  States  Surveyor  General 
at  Helena. 

Nebraslca. — Acquired  under  the  Louisiana  Purchase,  in  1803,  and 
admitted  into  the  Union  March  1,  1867  (14  Stat..  391,  and  14  Stat., 
820) ;  surveys  practically  completed  and  original  records  transferred 
to  the  Commissioner  of  Public  Lands  and  Buildings  at  Lincoln. 

Nevada. — Ceded  by  Mexico  in  1848  and  admitted  into  the  Union 
October  13, 1864  (13  Stat,  30,  and  13  Stat.,  749);  surveys  in  progress; 
United  States  Surveyor  General  at  Reno. 

New  Mexico. — Included  with  lands  annexed  with  Texas,  in  1845, 
with  lands  ceded  by  Mexico,  in  1848,  and  the  Gadsden  Purchase,  in 
1853,  and  admitted  into  the  Union  January  6,  1912  (36  Stat.,  557, 
and  37  Stat.,  1723);  surveys  in  progress;  United  States  Surveyor 
General  at  Santa  Fe. 

North  Dakota. — Included  in  the  territory  of  the  original  thirteen 
States,  and  with  lands  acquired  under  the  Louisiana  Purchase,  in 
1803,  and  admitted  into  the  Union  November  2, 1889  (25  Stat.,  676, 
and  26  Stat.,  1548);  surveys  practically  completed  and  original  rec- 
ords transferred  to  the  State  Engineer  at  Bismarck. 

Oklahoma.— Acquired  under  the  Louisiana  Purchase,  in  1803,  and 
with  lands  annexed  with  Texas,  in  1845,  and  admitted  into  the 
Union  November  16,  1907:(34  Stat.,  267,  and  35  Stat.,  2160);  surveys 
practically  completed  and  original  records  filed  with  the  Commis- 
sioner of  the  General  Land  Office  at  Washington,  D.  C. 

Ohio. — Included  in  the  territory  of  the  original  thirteen  States, 
and  admitted  into  the  Union  April  30,  1802  (2  Stat.,  173);  surveys 
practically  completed  and  original  records  transferred  to  the  Auditor 
of  State  at  Columbus. 

Oregon.— Included  in  the  Oregon  Territory,  title  to  which  .was 
established  in  184.6,  and  admitted  into  the  Union  February  14, 
1859  (11  Stat.,  383);  surveys  in  progress;  United  States  Surveyor 
General  at  Portland.  ,  , 

South  Dakota. — Included  in  the  territory  of  the  original  thirteen 
States,  and  with  lands  acquired  under  the  Louisiana  Purchase,  in 


4  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

1803,  and  admitted  into  the  Union  November  2,  1889  (25  Stat.,  676, 
and  26  Stat.,  1549);  surveys  in  progress;  United  States  Surveyor 
General  at  Huron. 

Utah. — Ceded  by  Mexico  in  1848,  and  admitted  into  the  Union 
January  4, 1896  (28  Stat..  107,  and  29  Stat.,  876);  surveys  in  progreas; 
United  States  Surveyor  General  at  Salt  Lake  City. 

Washington. — Included  in  the  Oregon  Territory,  title  to  which 
was  established  in  1846,  and  admitted  into  the  Union  November  11, 
1889  (25  Stat.,  676,  and  26  Stat.,  1552);  surveys  in  progress;  United 
States  Surveyor  General  at  Olympia. 

Wisconsin. — Included  in  the  territory  of  the  original  thirteen 
States,  and  admitted  into  the  Union  May  29,  1848  (9  Stat.,  233); 
surveys  practically  completed  and  original  records  transferred  to 
the  Commissioners  of  Public  Lands  at  Madison. 

Wyoming. — Included  with  lands  acquired  under  the  Louisiana 
Purchase,  in  1803,  with  lands  annexed  with  Texas,  in  1845,  with 
lands  included  in  the  Oregon  Territory,  title  to  which  was  estab- 
lished in  1846,  and  with  lands  ceded  by  Mexico,  in  1848,  and 
admitted  into  the  Union  July  10,  1890  (26  Stat.,  222);  surveys  in 
progress;  United  States  Surveyor  General  at  Cheyenne. 

District  of  Alaska. — Ceded  by  Russia  in  1867;  surveys  in  progress; 
United  States  Surveyor  General  at  Juneau. 

2.  After  the  admission  of  the  States  into  the  Union  the  United 
States  continued  to  hold  title  to  the  unappropriated  lands  and  to 
administer  its  public-land  laws  with  reference  thereto,  and  it  is  ex- 
pressly provided,  as  one  of  the  conditions  set  forth  in  the  various 
enabling  acts,  that  the  title  to  unappropriated  lands  within  the 
State  shall  remain  in  the  United  States.    The  lands  in  the  Territo- 
ries not  appropriated  by  competent  authority  before  they  were 
acquired  are  in  the  first  instance  the  exclusive  property  of  the 
United  States,  to  be  disposed  of  to  such  persons,  at  such  times, 
in  such  modes,  and  by  such  titles  as  the  Government  may  deem 
most  advantageous  to  the  public.    Congress  alone  has  the  power, 
derived  from  Article  IV,  section  3,  of  the  Constitution,  of  disposing 
of  the  public  domain  and  making  all  needful  rules  and  regulations 
in  respect  thereto. 

3.  Under  the  laws  of  the  United  States  the  navigable  waters  have 
always  been  and  shall  forever  remain  common  highways,  and  below 
mean  high  water  the  same  are  not  subject  to  survey  and  disposal. 
This  reservation  includes  all  tidewater  streams,  and  other  important 
permanent  bodies  of  water  whose  natural  and  normal  condition  at 


REGULATIONS  IMPOSED  BY  L.AW.  & 

the  date  of  the  admission  of  a  State  into  the  Union  was  such  as  to 
classify  the  same  as  navigable  water. 

4.  The  act  of  Congress  approved  March  2,  1849  (9  Stat.,  352), 
granted  to  the  State  of  Louisiana  all  the  swamp  and  overflowed 
lands  within  the  limits  of  the  State  for  the  purpose  of  aiding  in  the 
reclamation  of  said  lands,  and  the  act  of  Congress  approved  Sep- 
tember 28,  1850  (9  Stat.,  519),  extended  the  grant  to  the  other  public 
land  States  then  in  the  Union.     The  grant  was  also  extended  to  the 
States  of  Minnesota  and  Oregon  by  the  act  of  Congress  approved 
March  12,  1860  (12  Stats.,  3).     The  provisions  of  the  aforementioned 
grants  apply  to  the  zone  situated  below  the  uplands  wherein  the 
lands  are  of  such  a  character  that  without  the  construction  of  suit- 
able levees  and  artificial  drainage  systems  the  same  would  be  wet 
and  unfit  for  agricultural  purposes.     The  swamp-land  grants  apply 
to  all  swamp  and  overflowed  lands  within  the  beneficiary  States 
which  were  unappropriated  at  the  dates  of  the  acts  of  Congress  and 
whose  character  at  that  tune,  would  bring  them  within  the  provi- 
sions of  said  grants.     A  notable  exception  to  the  swamp-land  laws 
is  found  in  the  Arkansas  Compromise  Act  approved  April  29,  1898 
(30  Stat.,  367),  by  virtue  of  which  all  right,  title,  and  interest  to 
the  remaining  unappropriated  swamp  and  overflowed  lands  within 
the  State  of  Arkansas  reverted  to  the  United  States. 

5.  It  comes  within  the  province  of  the  Department  of  the  Inte- 
rior to  consider  and  determine  what  are  public  lands,  what  lands 
have  been  surveyed,  what  are  to  be  surveyed,  what  have  been  dis- 
posed of,%  what  remain  to  be  disposed  of,  and  what  are  reserved,  and 
it  is  a  well-settled  principle  of  law  that  the  United  States,  through 
the  Department  of  the  Interior,  has  the  right  to  extend  the  surveys 
as  may  be  necessary  to  include  lands  omitted  from  earlier  surveys. 
It  is  an  important  duty  of  the  surveyor  in  the  field  to  discriminate 
between  what  are  and  what  are  not  public  lands  of  the  United 
States  and  to  subdivide  the  former  in  accordance* with  the  regula- 
tions imposed  by  law. 

TAWS   RELATING  TO   SURVEYS. 

6.  The  rectangular  surveying  system  is  based  upon  existing  law 
and  was  devised  with  the  object  of  marking  upon  the  ground  and 
fixing  for  all  time  legal  subdivisions  for  purposes  of  description  and 
disposal  of  the  public  domain  under  the  general  land  laws  of  the 
United  States. 

7.  The  rectangular  system  of  survey  of  the  public  lands  was  inau^ 
gurated  by  a  committee  appointed  by  the  Continental  Congress. 


6 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


On  the  7th  of  May,  1784,  this  committee  reported  "An  ordinance 
for  ascertaining  the  mode  of  locating  and  disposing  of  lands  in  the 
western  territory,  and  for  other  purposes  therein  mentioned."  The 
ordinance  as  finally  passed  on  the  20th  of  May,  1785,  provided  for 
townships  6  miles  square,  containing  36  sections  of  1  mile  square. 
The  first  public  surveys  were  made  under  this  ordinance.  The 
townships,  6  miles  square,  were  laid  out  in  ranges  extending  north- 
ward from  the  Ohio  River,  the  townships  being  numbered  from 
south  to  north,  and  the  ranges  from  east  to  west.  The  region  em- 
braced by  the  surveys  under  this  law  forms  a  part  of  the  State  of 
Ohio.  In  these  initial  surveys  only  the  exterior  lines  of  the  town- 
ehips  were  surveyed,  but  the  plats  were  marked  by  subdivisions 
into  sections  of  1  mile  square,  and  mile  corners  were  established  on 


6 

5 

4 

3 

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7 

8 

9 

JO 

11 

12 

18 

17 

16 

15 

14 

\3 

19 

20 

2! 

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25 

31 

32 

33 

34 

35 

36 

the  township  lines.  The  sections  were  numbered  from  1  to  36,  and 
the  surveys  were  made  under  the  direction  of  the  Geographer  of 
the  United.  States. 

The  act  of  Congress  approved  May  18,  1796,  provided  for  the 
appointment  of  a  surveyor  general  and  directed  the  survey  of  the 
lands  northwest  of  the  Ohio  River  and  above  the  mouth  of  the  Ken- 
tucky River,  "in  which  the  titles  of  the  Indian  tribes  have  been 
extinguished."  Under  this  law  it  was  provided  that  "the  sections 
shall  be  numbered,  respectively,  beginning  with  the  number  one 
in  the  northeast  section  and  proceeding  west  and  east  alternately 
through  the  township,  with  progressive  numbers  till  the  thirty-sixth 
be  completed."  This  method  of  numbering  sections,  as  shown  by 
the  accompanying  diagram,  is  still  in  use. 


REGULATIONS  IMPOSED  BY  LAW.  7 

The  act  of  Congress  approved  May  10,  1800,  required  the  "town- 
ships west  of  the  Muskingum,  which  *  *  *  are  directed  to  be 
sold  in  quarter  townships,  to  be  subdivided  into  half  sections  of 
three  hundred  and  twenty  acres  each,  as  nearly  as  may  be,  by  run- 
ning parallel  lines  through  the  same  from  east  to  west  and  from  south 
to  north  at  the  distance  of  one  mile  from  each  other,  and  marking1 
corners  at  the  distance  of  each  half  mile  on  the  lines  running  from 
east  to  west  and  at  the  distance  of  each  mile  on  those  running  from 
south  to  north.  *  *  *  And  the  interior  lines  of  townships  inter- 
sected by  the  Muskingum,  and  of  all  the  townships  lying  east  of 
that  river,  which  have  not  been  heretofore  actually  subdivided  into 
sections  shall  also  be  run  and  marked.  *  *  *  And  in  all  cases 
where  the  exterior  lines  of  the  townships  thus  to  be  subdivided  into 
sections  or  half  sections  shall  exceed,  or  shall  not  extend,  six  miles, 
the  excess  or  deficiency  shall  be  specially  noted  and  added  to  or 
deducted  from  the  western  and  northern  ranges  of  sections  or  half 
sections  in  such  townships,  according  as  the  error  may  be  in  run- 
ning the  lines  from  east  to  west  or  from  south  to  north." 

The  act  of  Congress  approved  February  11,  1805,  directs  the  sub- 
division of  the  public  lands  into  quarter  sections  and  provides  that 
all  the  corners  marked  in  the  public  surveys  shall  be  established 
as  the  proper  corners  of  sections,  or  subdivisions  of  sections,  which 
they  were  intended  to  designate,  and  that  corners  of  half  and  quar- 
ter sections  not  marked  shall  be  placed  as  nearly  as  possible  "equi- 
distant from  those  two  corners  which  stand  on  the  same  line." 
This  act  further  provides  that  ' '  The  boundary  lines  actually  run 
and  marked  *  *  *  shall  be  established  as  the  proper  boundary 
lines  of  the  sections  or  subdivisions  for  which  they  were  intended; 
and  the  length  of  such  lines  as  returned  by  *  *  •*  the  survey- 
ors *  *  *  shall  be  held  and  considered  as  the  true  length  thereof, 
and  the  boundary  lines  which  shall  not  have  been  actually  run  and 
marked  as  aforesaid  shall  be  ascertained  by  running  straight  lines 
from  the  established  corners  to  the  opposite  corresponding  corners; 
but  in  those  portions  of  the  fractional  townships  where  no  such  oppo- 
site or  corresponding  corners  have  been  or  can  be  fixed,  the  said 
boundary  lines  shall  be  ascertained  by  running  from  the  established 
corners  due  north  and  south  or  east  and  west  lines,  as  the  case  may 
be,  to  the  *  *  *  external  boundary  of  such  fractional  town- 
ship." 

•:  The,,  act  of  Congress  approved  April   25,  1812,  provided  "That 
there  shall  be  established  in  the  Department  of  the  Treasury  an 


8  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

office  to  be  denominated  the  General  Land  Office,  the  chief  officer 
of  which  shall  be  called  the  Commissioner  of  the  General  Land 
Office,  whose  duty  it  shall  be,  under  the  direction  of  the  head  of 
the  department,  to  superintend,  execute,  and  perform  all  such  acts 
and  things  touching  or  respecting  the  public  lands  of  the  United 
States,  and  other  lands  patented  or  granted  by  the  United  States, 
as  have  heretofore  been  directed  by  law  to  be  done  or  performed  in 
the  office  of  the  Secretary  of  State,  of  the  Secretary  and  Register  of 
the  Treasury,  and  of  the  Secretary  of  War,  or  which  shall  hereafter 
by  law  be  assigned  to  the  said  office." 

The  act  of  Congreas  approved  April  24,  1820,  provides  for  the  sale 
of  public  lands  in  half-quarter  sections,  and  requires  that  "in  every 
case  of  the  division  of  a  quarter  section  the  line  for  the  division 
thereof  shall  run  north  and  south  *  *  *  and  fractional  sections, 
containing  one  hundred  and  sixty  acres  and  upward,  shall,  in  like 
manner,  as  nearly  as  practicable,  be  subdivided  into  half-quarter 
sections,  under  such  rules  and  regulations  as  may  be  prescribed  by 
the  Secretary  of  the  Treasury;  but  fractional  sections  containing 
less  than  one  hundred  and  sixty  acres  shall  not  be  divided." 

The  act  of  Congress  approved  May  29,  1830  (sees.  2412,  2413,  R. 
S.),  provides  for  the  fine  and  imprisonment  of  any  person  obstructing 
the  survey  of  the  public  lands,  and  for  the  protection  of  surveyors,  in 
the  discharge  of  their  official  duties,  by  the  United  States  marshal, 
with  sufficient  force,  whenever  necessary. 

The  act  of  Congress  approved  April  5,  1832,  directed  the  sub- 
division of  the  public  lands  into  quarter  quarters;  that  in  every  ease 
of  the  division  of  a  half-quarter  section  the  dividing  line  should  run 
east  and  west;  and  that  fractional  sections  should  be  subdivided 
under  rules  and  regulations  prescribed  by  the  Secretary  of  tha 
Treasury.  Under  the  latter  provision  the  Secretary  directed  that 
fractional  sections  containing  less  than  160  acres,  or  the  residuary 
portion  of  a  fractional  section,  after  the  subdivision  into  as  many 
quarter-quarter  sections  as  it  is  susceptible  of,  may  be  subdivided 
into  lots,  each  containing  the  quantity  of  a  quarter-quarter  section 
as  nearly  as  practicable,  by  so  laying  down  the  line  of  subdivision 
that  they  shall  be  20  chains  wide,  which  distances  are  to  be  marked 
on  the  plat  of  subdivision,  as  are  also  the  areas  of  the  quarter  quarters 
and  residuary  fractions. 

The  last  two  acts  above  mentioned  provided  that  the  corners  and 
contents  of  half-quarter  and  quarter-quarter  sections  should  be  ascer- 


REGULATIONS  IMPOSED  BY  LAW.  9 

tained,  as  nearly  as  possible,  in  the  manner  and  on  the  principles 
directed  and  prescribed  in  the  act  of  Congress  approved  February 
11, 1805. 

The  act  of  Congress  approved  July  4,  1836,  provided  for  the  re- 
organization of  the  General  Land  Office,  and  that  the  executive 
duties  of  said  office  "shall  be  subject  to  the  supervision  and  control 
of  the  Commissioner  of  the  General  Land  Office  under  the  direction 
of  the  President  of  the  United  States."  The  repealing  clause  is, 
"That  such  provisions  of  the  act  of  the  twenty-fifth  of  April,  in  the 
year  one  thousand  eight  hundred  and  twelve,  entitled  'An  act  for 
the  establishment  of  a  General  Land  Office  in  the  Department  of 
the  Treasury,'  and  of  all  acts  amendatory  thereof,  as  are  incon- 
sistent with  the  provisions  of  this  act,  be,  and  the  same  are  hereby, 
repealed. " 

From  the  wording  of  this  act  it  would  appear  that  the  control  of 
the  General  Land  Office  was  removed  from  the  Treasury  Depart- 
ment, and  that  the  commissioner  reported  directly  to  the  President; 
but,  as  a  matter  of  fact,  the  Secretary  of  the  Treasury  still  had 
supervisory  control,  for  the  act  of  Congress  approved  March  3,  1849, 
by  which  the  Department  of  the  Interior  was  established,  provided, 
"That  the  Secretary  of  the  Interior  shall  perform  all  the  duties  in 
relation  to  the  General  Land  Office,  of  supervision  and  appeal,  now 
discharged  by  the  Secretary  of  the  Treasury  *  *  *."  By  this 
act  the  General  Land  Office  was  transferred  to  the  Department  of 
the  Interior,  where  it  still  remains. 

8.  The  following  comprises  so  much  of  the  general  laws  relating  to 
the  survey  of  the  public  domain  as  it  is  deemed  necessary  to  incor- 
porate in  this  volume,  reference  being  made  by  chapter  and  section 
to  the  codification  of  the  Public  Land  Laws,  prepared  pursuant  to 
acts  of  Congress  approved  March  3,  1879,  and  June  16,  1880,  and  by 
section  number  to  the  Revised  Statutes  of  the  United  States. 

SEC.  32.  The  Commissioner  of  the  General  Land  Office  shall  per- 
form, under  the  direction  of  the  Secretary  of  the 
C°m  Interior»  a11  executive  duties  appertaining  to  the 
surveying  and  sale  of  the  public  lands  of  the 
United  States,  or  in  anywise  respecting  such  public  lands;  and, 
also,  such  as  relate  to  private  claims  of  lands,  and  the  issuing  of 
patents  for  all  grants  of  land  under  the  authority  of  the  Govern- 
ment. (R.  S.,  453.) 

66466°~19 2 


10  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

SEC.  61.  The  Commissioner,  under  the  direction  of  the  Secretary 

of  the  Interior,  is  authorized  to  enforce  and  carry 
Power    of    Com-    -^  execution  every  part  of  the  public  j     d  j 
missioner  to  make  .  f  f 

regulations.  not  otherwise  specially    provided    for.      (R.    S., 

2478.) 

SEC.  77.  There  shall  be  appointed  by  the  President,  by  and  with 

the  advice  and  consent  of  the  Senate,  a  surveyor 

Surveyor  general,   generai  f  or  fae  states  and  Territories  herein  named, 

how  and  where  ap-          , 

pointed.  embracing,   respectively,  one  surveying  district, 

namely:  Louisiana,  Florida,  Minnesota,  Kansas, 
California,  Nevada,  Oregon,  Nebraska  and  Iowa,  Dakota,  Colorado, 
New  Mexico,  Idaho,  Washington,  Montana,  Utah,  Wyoming,  Arizona. 
(R.S.,2207.) 

SEC.  83.  Every  surveyor  general,  while  in  the  discharge  of  the 
Residence  of  sur-   duties  of  his  office,  shall  reside  in  the  district  for 
veyor  general.  which  he  is  appointed.     (R.  S.  2214.) 

SEC.  84.  Every  surveyor  general  shall,  before  entering  on  the 
duties  of  his  office,  execute  and  deliver  to  the 


ene°raf  °'  ^^^  Secretary  of  the  Interior  a  bond,  with  good  and 

sufficient  security,   for  the  penal  sum  of  thirty 

thousand  dollars,  conditioned  for  the  faithful    disbursement,  ac- 

cording to  law,  of  all  public  money  placed  in  his  hands,  and  for 

the  faithful  performance  of  the  duties  of  his  office;  and  the  Presi- 

dent has  discretionary  authority  to  require  a  new  bond  and  additional 

security,  under  the  direction  of  the  Secretary  of  the  Interior,  for  the 

lawful  disbursement  of  public  moneys.     (R.  S.,  2215,  2216.) 

SEC.  85.  The  commission  of  each  surveyor  general  shall  cease  and 

expire  in  four  years  from  the  date  thereof,  unless 
Duration  of  office. 

sooner  vacated  by  death,  resignation,  or  removal 

from  office.    (R.  S.,  2217.) 

SEC.  86.  Every  surveyor  general,  except  where  the  President  sees 
Continuance     of  cause  otherwise  to  determine,  is  authorized  to  con- 
duties    and    bond  tinue  in  the  uninterrupted  discharge  of  his  regular 
after  expiration  of  official  duties  after  the  day  of  expiration  of  hie 
commission.  commission  and  until  a  new  commission  is  issued  to 

him  for  the  same  office,  or  until  the  day  when  a  successor  enters  upon 
the  duties  of  such  office;  and  the  existing  official  bond  of  any  officer 
eo  acting  shall  be  deemed  good  and  sufficient  and  in  force  until  the 
date  of  the  approval  of  the  new  bond  to  be  given  by  him,  if  recom- 
missioned,  or  otherwise,  for  the  additional  time  he  may  so  continue 


KEGULAT1ONS  IMPOSED  BY  JLA\\ '.  11 

officially  to  act,  pursuant  to  the  authority  of  this  section.  (R.  S., 
2222.) 

SEC.  87.  Whenever  the  surveys  and  records  of  any  surveying  die- 
Transfer  of  papers  tr*ct  are  completed  the  surveyor  general  thereof 
and  discontinuance  shall  be  required  to  deliver  over  to  the  secretary 
of  office  in  case  of  of  state  of  the  respective   States,  including  such 
completed  surveys.    surveys>  or  to  8Uch  other  officer  as  may  be  authorized 

to  receive  them,  all  the  field  notes,  maps,  records,  and  other  papers 
appertaining  to  land  titles  within  the  name ;  and  the  office  of  surveyor 
general  in  every  such  district  shall  thereafter  cease  and  be  discon- 
tinued. (R.S.,2218.) 

SEC.  88.  In  all  cases  of  discontinuance,  as  provided  in  the  preced- 
ing section,  the  authority,  powers,  and  duties  of 

Devolution  of  ^  surveyor  general  in  relation  to  the  survey,  re- 
powers  upon  Com-  .....  »  .,  ,'  .  .  '  „ 
missioner  in  case  of  aurvey>  or  subdivision  of  the  lands  therein,  and  all 
discontinuance.  matters  and  things  connected  therewith,  shall  be 
vested  in  and  devolved  upon  the  Commissioner  of 
the  General  Land  Office.  (R.  S.,  2219.) 

SEC.  89.  Under  the  authority  and   direction    of   the   Commis- 
sioner of   the   General  Land  Office  any  deputy 

Free  access  to  surveyor  or  other  agent  of  the  United  States  shall 
public  records  de-  have  free  accega  to  h  field  ^ 

livered    to    States, 
and    condition    of  records,    and    other   papers   for    the    purpose   of 

such  delivery.  takin  g    extracts    therefrom    or   making    copies 

thereof  without  charge  of  any  kind;  but  no  transfer 
of  such  public  records  shall  be  made  to  the  authorities  of  any  State 
until  such  State  has  provided  by  law  for  the  reception  and  safe- 
keeping of  such  public  records,  and  for  the  allowance  of  free  access 
thereto  by  the  authorities  of  the  United  States.     (R.  S.,  2220,  2221.) 
SEC.  99.  First.  The  public  lands  shall  be  divided  by  north  and 
R  south  lines  run  according  to  the  trur;  meridian,  and 

by  others  crossing  them  at  right  angles,  so  as  to 
form  townships  of  six  miles  square,  unless  where  the  line  of  an  In- 
dian reservation,  or  of  tracts  of  land  heretofore  surveyed  or  pat- 
ented, or  the  course  of  navigable  rivers,  may  render  this  impracti- 
cable ;  and  in  that  case  this  rule  must  be  departed  from  no  further 
than  such  particular  circumstances  require. 

Second.  The  corners  of  the  townships  must  be  marked  with  pro- 
gressive numbers  from  the  beginning;  each  distance  of  a  mile  between 
such  corners  must  be  also  distinctly  marked  with  marks  different 
from  those  of  the  corners. 


]  2  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

Third.  The  township  shall  be  subdivided  into  sections,  containing 
as  nearly  as  may  be,  six  hundred  and  forty  acres  each,  by  running; 
through  the  same,  each  way,  parallel  lines  at  the  end  of  every  two 
miles1;  and  by  making  a  corner  on  each  of  such  lines  at  the  end  of 
every  mile.  The  sections  shall  be  numbered,  respectively,  begin- 
ning with  the  number  one  in  the  northeast  section,  and  proceeding 
west  and  east  alternately  through  the  township  with  progressive 
numbers  till  the  thirty-six  be  completed. 

Fourth.  The  deputy  surveyors,  respectively,  shall  cause  to  be 
marked  on  a  tree  near  each  corner  established  in  the  manner  de- 
scribed, and  within  the  section,  the  number  of  such  section,  and 
over  it  the  number  of  the  township  within  which  such  section  may 
be;  and  the  deputy  surveyors  shall  carefully  note,  in  their  respective 
field  books,  the  names  of  the  corner  trees  marked  and  the  numbers 
so  made. 

Fifth.  Where  the  exterior  lines  of  the  townships  which  may  be 
subdivided  into  sections  or  half  sections  exceed,  or  do  not  extend 
six  miles,  the  excess  or  deficiency  shall  be  specially  noted,  and  added 
to  or  deducted  from  the  western  and  northern  ranges  of  sections  or 
half  sections  in  such  townships,  according  as  the  error  may  be  in 
running  the  lines  from  east  to  west,  or  from  south  to  north ;  the  sec- 
tions and  half  sections  bounded  on  the  northern  and  western  lines 
of  such  townships  shall  be  sold  as  containing  only  the  quantity 
expressed  in  the  returns  and  plats,  respectively,  and  all  others  as 
containing  the  complete  legal  quantity. 

Sixth.  All  lines  shall  be  plainly  marked  upon  trees,  and  measured 
with  chains,  containing  two  perches  of  sixteen  and  one-half  feet 
each,  subdivided  into  twenty-five  equal  links;  and  the  chain  shall  be 
adjusted  to  a  standard  to  be  kept  for  that  purpose.2 

Seventh.  Every  surveyor  shall  note  in  h}s  field  book  the  true 
situations  of  all  mines,  salt  licks,  salt  springs,  and  mill  seats  which 
come  to  his  knowledge;  all  water  courses  over  which  the  line  he  runs 
may  pass ;  and  also  the  quality  of  the  lands. 

Eighth.  These  field  books  shall  be  returned  to  the  surveyor  gen- 
eral, who  shall  cause  therefrom  a  description  of  the  whole  lands  sur- 

1  Authority  for  the  establishment  of  section  lines  at  intervals  of  1  mile  is  found 
in  the  act  of  Congress  approved  May  10,  1800,  previously  quoted. 

2  The  superior  results  obtained  by  the  use  of  modern  steel  ribbon  tapes,  in  con- 
trast with  the  obsolete  link  chain,  have  led  to  the  abandonment  of  the  latter, 
except  that  the  "chain  unit,"  which  is  peculiarly  adapted  to  land  surveying,  has 
always  been  employed. 


REGULATIONS  IMPOSED  BY  LAW.  13 

veyed  to  be  made  out  and  transmitted  to  the  officers  who  may 
superintend  the  sales.  He  shall  also  cause  a  fair  plat  to  be  made 
of  the  townships  and  fractional  parts  of  townships  contained  in  the 
lands,  describing  the  subdivisions  thereof,  and  the  marks  of  the 
corners.  This  plat  shall  be  recorded  in  books  to  be  kept  for  that 
purpose;  and  a  copy  thereof  shall  be  kept  open  at  the  surveyor 
general's  office  for  public  information,  and  other  copies  shall  be 
sent  to  the  places  of  the  sale  and  to  the  General  Land  Office.  (Acts 
of  May  18,  1796,  and  May  10,  1800,  and  R.  S.,  2395.) 

SEC.  100.  The  boundaries  and  contents  of  the  several  sections,  half 

Boundaries  and  secti°ns>  an(*  quarter  sections  of  the  public  lands 
contents  of  public  shall  be  ascertained  in  conformity  with  the  follow- 
lands,  how  ascer-  ing  principles : 

tained-  First.  All  the  corners  marked  in  the  surveys 

returned  by  the  surveyor  general  shall  be  established  as  the  proper 
corners  of  sections,  or  subdivisions  of  sections,  which  they  were 
intended  to  designate,  and  the  corners  of  half  and  quarter  sections, 
not  marked  on  the  surveys,  shall  be  placed  as  nearly  as  possible 
equidistant  from  two  corners  which  stand  on  the  same  line. 

Second.  The  boundary  lines,  actually  run  and  marked  in  the 
surveys  returned  by  the  surveyor  general,  shall  be  established  as 
the  proper  boundary  lines  of  the  sections  or  subdivisions  for  which 
they  were  intended,  and  the  length  of  such  lines  as  returned  shall  be 
held  and  considered  as  the  true  length  thereof.  And  the  boundary 
lines  which  have  not  been  actually  run  and  marked  shall  be  ascer- 
tained by  running  straight  lines  from  the  established  corners  to  the 
opposite  corresponding  corners;  but  in  those  portions  of  the  fractional 
townships,  where  no  such  opposite  corresponding  corners  have  been 
or  can  be  fixed,  the  boundary  lines  shall  be  ascertained  by  running 
from  the  established  corners  due  north  and  south  or  east  and  west 
lines,  as  the  case  may  be,  to  the  water  course,  Indian  boundary 
line,  or  other  external  boundary  of  such  fractional  township. 

Third.  Each  section  or  subdivision  of  section,  the  contents  whereof 
have  been  returned,  by  the  surveyor  general,  shall  be  held  and 
considered  as  containing  the  exact  quantity  expressed  in  such  return; 
and  the  half  sections  and  quarter  sections,  the  contents  whereof 
shall  hot  have  been  thus  returned,  shall  be  held  and  considered  as 
containing  the  one-half  or  the  one-fourth  part,  respectively,  of  the 
returned  contents  of  the  section  of  which  they  may  make  part. 
(Act  of  Feb.  11,  1805,  and  K.  S.,  2396.) 


14  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

BBS.  '101.  In  every  case  of  the  division  of  a  quarter  section  the 
line  for  the  division  thereof  shall  run  north  and 

r^Uw  °f  ^ivision    south,  and  the  corners  and  contents  of  half-quarter 
of  half-quarter  sec-  ,  .  , 

tiom,  how  ran.  sections  which  may  thereafter  be  sold  shall  be 

ascertained  in  the  manner  and  on  the  principles 
directed  and  prescribed  by  the  section  preceding,  and  fractional 
sections  containing  one  hundred  and  sixty  acres  or  upwards  shall  in 
like  mariner,  as  nearly  as  practicable,  be  subdivided  into  half- 
quarter  sections,  under  such  rules  and  regulations  as  may  be  pre- 
scribed by  the  Secretary  of  the  Interior,  and  in  every  case  of  a  division 
of  a  half-quarter  section,  the  line  for  the  division  thereof  shall  run 
east  and  west,  and  the  corners  and  contents  of  quarter-quarter  sec- 
tions, which  may  thereafter  be  sold,  shall  be  ascertained,  as  nearly 
as  may  be.  in  the  manner  and  on  the  principles  directed  and  pre- 
scribed by  the  section  preceding;  and  fractional  sections  containing 
fewer  or  more  than  one  hundred  and  sixty  acres  shall  in  like  manner, 
as  noaiiy  as  may  be  practicable,  be  subdivided  into  quarter-quarter 
sections,  under  such  rules  and  regulations  as  may  be  prescribed  by 
the  Secretary  of  the  Interior.  (R.  S.,  2397.) 

•  SEC.  106.  The  public  surveys  shall  extend  over  all  mineral  lauds, 

and  all  subdividing  of  surveyed  lands  into  lots  less 
Extension  of  pub-    tjian  one  hundred  and  sixty  acres  may  be  done  by 
county  and  local  surveyors  at  the  expense  of 
claimants;  but  nothing  in  this  section  contained 
shall  require  the  survey  of  waste  or  useless  lands.     (R.  S.,  2406.) 
SEC.  118.  Each  surveyor  general,  when  thereunto  duly  authorized 
by  law,  shall  cause  all  confirmed  private  land 
Surveyors  general    claims  within  his  district  to  be  accurately  siir- 
to  surve^spr^^    veyed,  and  shall  transmit  plats  and  field  notes 
confirmed,  etc.  thereof  to  the  Commissioner  of  the  General  Land 

Office  for  his  approval .  When  publication  of  such 
surveys  is  authorized  by  law,  the  proof  thereof,  together  with  any 
objections  properly  filed,  and  all  evidence  submitted  either  in  sup- 
port of  or  in  opposition  to  the  approval  of  any  such  survey,  shall  also 
be  transmitted  to  said  Commissioner.  (R.  S.,  2447.) 
SEC.  120.  Every  person  who  in  any  manner,  by  threat  or  force, 

*  interrupts,  hinders,  or  prevents  the  surveying  of 
Penalty  for  inter-    ^  public  lan(js?  or  of  any  private  land  claim 

which  has  been  or  may  be  confirmed  by  the 
United  Slates,  by  the  persons  authorized  to  survey  the  same,  in 
conformitv  with  the  instructions  of  the  Commissioner  of  the  Gen- 


REGULATIONS  IMPOSED  BY  LAW.  15 

eral  Land  Office,  shall  be  fined  not  less  than  fifty  dollars,  nor  more 
than  three  thousand  dollars,  and  be  imprisoned  not  less  than  one  nor 
more  than  three  years.  (R.S.,2412.) 

SEC.  121.  Whenever  the  President  is  satisfied  that  forcible  oppo- 
sition has  been  offered,  or  is  likely  to  be  offered, 

Protection  of  sur-  to  any  8UrveyOr  or  deputy  surveyor  in  the  dis- 
veyor  by  marshal  of  ,  ,. ,  .  , ,  ,.  .  ,,  ,  ..  ,  , 

district  charge  of  his  duties  in  surveying  the  public  lands, 

it  may  be  lawful  for  the  President  to  order  the 
marshal  of  the  State  or  district,  by  himself  or  deputy,  to  attend  such 
surveyor  or  deputy  surveyor  with  sufficient  force  to  protect  such 
officer  in  the  execution  of  his  duty,  and  to  remove  force  should  any 
be  offered.  (R.  S.,  2413.) 

9.  More  recent  legislation  has  brought  about  (a)  provision  for  the 
appointment  of  a  United  States  Surveyor  General  for  the  District 
of  Alaska;  (6)  authority  for  the  purchase  of  durable  monuments,  to  be 
employed  in  place  of  native  material  to  mark  public  land  corners; 
(c)  penalty  for  the  destruction  of  monuments  of  the  public  land 
surveys;  (d)  authority  for  necessary  resurveys;  and  (e)  change  of 
survey  system  from  contract  to  direct  with  authority  for  the  em- 
ployment of  a  permanent  corps  of  United  States  surveyors;  all  as 
indicated  by  the  following  quotations  from  the  United  States 
Statutes: 

The  act  of  Congress  approved  May  17,  1884,  providing  a  civil 
government  for  Alaska,  provides  "That  the  said 

Surveyor  general  District  of  Alaska  is  hereby  created  a  land  dis- 
for  the  District  of,.,.,.,,,  ...  *  i  -jj/u 

Aiaska  tnct,  r    and  the  marshal  provided  for  by 

this  act  shall  be  ex  officio  surveyor  general  of  said 

district."     (23  Stat.,  24,  sec.    8.)    The  act  of  Congress  approved 

July  24,  1897,  amends  the  act  approved  May  17,  1884,  and  provides 

"That  there  shall  be  appointed  by  the  President,  by  and  with  the 

advice  and  consent  of  the  Senate,  a  surveyor  generarfor  the  District 

of  Alaska,  embracing  one  surveying  district. ' '     (30  Stat. ,  215,  sec .  2. ) 

The  act  of  Congress  approved  May  27,  1908,  provided  "for  the 

purchase  of  metal  monuments  to  be  used  for 

public  land  survey  corners  wherever  practicable. >r 

(35  Stat.,  347.)    This  authority  was  amplified  by 

the  act  of  Congress  approved  June  25, 1910,  making  appropriation 

for  sundry  civil  expenses  for  the  fiscal  year  ended  June  30,1911, 

and  has  been  continued  from  year  to  year  to  the  present  time; 

The  act  approved  July  1,  1918,  provided,  under  "Surveying  the 

Public  Lands."  as  follows: 


16  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

''That  the  sum  of  not  exceeding  10  per  centum  of  the  amount 
hereby  appropriated  may  be  expended  by  the  Commissioner  of  the 
General  Land  Office,  with  the  approval  of  the  Secretary  of  the 
Interior,  for  the  purchase  of  metal  or  other  equally  durable  monu- 
ments to  be  used  for  public  land  survey  corners  wherever  practi- 
cable: *  *  *."  (40  Stat.,  668.) 

The  act  of  Congress  approved  March  4.  1909,  entitled  "An  act  to 

penalty  for  the  c°d^y>  revise,  and  amend  the  penal  laws  of  the 
destruction  of  sur-  United  States,"  provides  punishment  for  offenses 
vey  monuments.  against  the  operation  of  the  surveying  service  of  the 
Government,  as  follows: 

"Whoever  shall  willfully  destroy,  deface,  change,  or  remove  to 
another  place  any  section  corner,  quarter-section  corner,  or  meander 
post,  on  any  Government  line  of  survey,  or  shall  willfully  cut  down 
any  witness  tree  or  any  tree  blazed  to  mark  the  line  of  a  Government 
survey,  or  shall  willfully  deface,  change,  or  remove  any  monument 
or  bench  mark  of  any  Government  survey,  shall  be  fined  not  more 
than  $250,  or  imprisoned  not  more  than  six  months,  or  both."  (35 
Stat.,  1088,  sec.  57.) 

The  act  of  Congress  approved  March  3,  1909,  entitled  "An  act 
authorizing  the  necessary  resurvey  of  public 
°  "  lands,"  as  amended  by  joint  resolution  approved 
June  25,  1910,  provides  as  follows: 

"That  the  Secretary  of  the  Interior  may,  in  his  discretion,  cause 
to  be  made,  as  he  may  deem  wise  under  the  rectangular  system  now 
provided  by  law,  such  resurvey s  or  retracements  of  the  surveys  of 
public  lands  as,  after  full  investigation,  he  may  deem  essential  to 
properly  mark  the  boundaries  of  the  public  lands  remaining  undis- 
posed of:  Provided,  That  no  such  resurvey  or  retracement  shall  be  so 
executed  as  to  impair  the  bona  fide  rights  or  claims  of  any  claimant, 
entryman,  or  owner  of  lands  affected  by  such  resurvey  or  retracement: 
Provided  further,  That  not  to  exceed  20  per  centum  of  the  total 
annual  appropriation  for  surveys  and  resurveys  of  the  public  lands 
shall  be  used  for  the  resurveys  and  retracements  authorized  here- 
by." (35  Stat.,  845,  and  36  Stat.,  884.) 

The  act  of  Congress  approved  September  21,  1918,  entitled  ' l  An 
act  authorizing  the  resurvey  or  retracement  of  lands  heretofore  re- 
turned as  surveyed  public  lands  of  the  United  States  under  certain 
conditions",  provides  authority  for  the  resurvey  by  the  Govern- 
ment of  townships  heretofore  held  to  be  ineligible  for  resurvey 


REGULATIONS  IMPOSED  BY  LAW.  17 

under  existing  regulations  of  the  Department  of  the  Interior  by 
reason  of  disposals  in  excess  of  fifty  per  centum  of  the  total  area 
thereof.  The  act  provides: 

"  That  upon  the  application  of  the  owners  of  three-fourths  of  the 
privately  owned  lands  in  any  township  covered  by  public-land 
surveys,  more  than  fifty  per  centum  of  the  area  of  which  townships 
is  privately  owned,  accompanied  by  a  deposit  with  the  United 
States  surveyor  general  for  the  proper  State,  or  if  there  be  no  sur- 
veyor general  of  such  State,  then  with  the  Commissioner  of  the 
General  Land  Office,  of  the  proportionate  estimated  cost,  inclusive 
of  the  necessary  (office)  work,  of  the  resurvey  or  retrace  ment  of  all 
the  privately  owned  lands  in  said  township,  the  Commissioner  of 
the  General  Land  Office,  subject  to  the  supervisory  authority  of  the 
Secretary  of  the  Interior,  shall  be  authorized  in  his  discretion  to 
cause  to  be  made  a  resurvey  or  retracement  of  the  lines  of  said 
township  and  to  set  permanent  corners  and  monuments  in  accord- 
ance with  the  laws  and  regulations  governing  surveys  and  resurveys 
of  public  lands;  that  the  sum  so  deposited  shall  be  held  by  the 
surveyor  general  or  commissioner  when  ex  officio  surveyor  general 
and  may  be  expended  in  payment  of  the  cost  of  such  survey,  in- 
cluding field  and  office  work,  and  any  excess  over  the  cost  of  such 
survey  and  the  expenses  incident  thereto  shall  be  repaid  pro  rata 
to  the  persons  making  said  deposits  or  their  legal  representatives; 
that  the  proportionate  cost  of  the  field  and  office  work  for  the  re- 
survey  or  retracement  of  any  public  lands  in  such  township  shall 
be  paid  from  the  current  appropriation  for  the  survey  and  resurvey 
of  public  lands,  in  addition  to  the  portion  of  such  appropriation 
otherwise  allowed  by  law  for  resurveys  and  retracements;  that 
similar  resurveys  and  retracements  may  be  made  on  the  applica- 
tion, accompanied  by  the  requisite  deposit,  of  any  court  of  compe- 
tent jurisdiction,  the  returns  of  such  resurvey  or  retracement  to  be 
submitted  to  the  court;  that  the  Secretary  of  the  Interior  is  author- 
ized to  make  all  necessary  rules  and  regulations  to  carry  this  act 
into  full  force  and  effect."  (40  Stat.,  965.) 

The  act  of  Congress  approved  June  25,  1910  (36  Stat.,  703,  740), 
making  appropriation  for  sundry  civil  expenses 
*  '"  for  the  fiscal  year  ended  June  30,  1911,  provided, 


under  "Surveying  the  Public  Lands":  "  The  sur- 
veys and  resurveys  to  be  made  by  such  competent  surveyors  as  the 
Secretary  of  the  Interior  may  select,  *  *  *  .  "  This  provision  of  law. 


18  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

brought  to  a  close  the  contract  system  which  had  theretofore  been 
adhered  to  since  the  beginning  of  the  public  land  surveys,  and 
the  authority  for  the  employment  of  a  permanent  corps  of  United 
States  surveyors  has  been  continued  from  year  to  year  to  the  pres- 
ent time.  The  following  comprises  that  part  of  the  act  of  Congress 
approved  July  1,  1918,  under  " Surveying  the  Public  Lands,"  re- 
lating directly  to  the  administrative  control  of  the  surveying  service: 
"For  surveys  and  resurveys  of  public  lands,  under  the  supervision 
of  the  Commissioner  of  the  General  Land  Office  and  direction  of  the 
Secretary  of  the  Interior,  *  *  *.  The  surveys  and  resurveys 
provided  for  in  this  appropriation  to  be  made  by  such  competent 
surveyors  as  the  Secretary  of  the  Interior  may  select,  *  *  *. " 
(40Stat.,  668.) 

GENERAL  RULES. 

10.  From  the  foregoing  synopsis  of  congressional  legislation  it  is 
evident — 

First.  That  the  boundaries  of  the  public  lands  established  and 
returned  by  the  duly  appointed  surveyors,  when  approved  by  the 
surveyors  general  and  accepted  by  the  Commissioner  of  the  General 
Land  Office,  are  unchangeable. 

Second.  That  the  original  township,  section,  and  quarter-section 
corners  established  by  the  surveyors  must  stand  as  the  true  corners 
which  they  were  intended  to  represent,  whether  in  the  place  shown 
by  the  field  notes  or  not. 

Third.  That  quarter-quarter-section  corners  not  established  in  the 
process  of  the  original  survey  shall  be  placed  on  the  line  connecting 
the  section  and  quarter-section  corners,  and  midway  between  them, 
except  on  the  last  half  mile  of  section  lines  closing  on  the  north  and 
west  boundaries  of  the  township,  or  on  other  lines  between  fractional 
or  irregular  sections. 

Fourth.  That  the  center  lines  of  a  regular  section  are  to  be  straight, 
running  from  the  quarter-section  corner  on  one  boundary  of  the  sec- 
tion to  the  corresponding  corner  on  the  opposite  section  line. 

Fifth.  That  in  a  fractional  section  where  no  opposite  corresponding 
quarter-section  corner  has  been  or  can  be  established,  the  center  line 
of  such  section  must  be  run  from  the  proper  quarter-section  corner 
as  nearly  in  a  cardinal  direction  to  the  meander  line,  reservation  or 
other  boundary  of  such  fractional  section,  as  due  parallelism  with 
section  lines  will  permit. 


REGULATIONS  IMPOSED  BY  LAW.  19 

Sixth.  That  lost  or  obliterated  corners  of  the  approved  surveys 
must  be  restored  to  their  original  locations  whenever  it  is  possible  to 
do  so.  Actions  or  decisions  by  surveyors  which  may  result  in 
changes  of  boundaries  of  patented  lands  and  disturb  questions  of 
ownership  in  connection  therewith  are  subject  to  review  by  the 
courts. 

THE   MANUAL. 

11.  Various  regions  of  the  United  States  have  been  surveyed 
under  different  sets  of  instructions  issued  at  periods  ranging  from 
1785  to  the  present  time.  The  earliest  rules  were  given  to  surveyors 
in  manuscript  or  in  printed  circulars.  Regulations  more  in  detail, 
improving  the  system  for  greater  accuracy,  permanency  and  uni- 
formity, were  issued  in  book  form  in  editions  of  1855,  1881,  1890, 
1894  and  1902. 

The  Manual  of  Surveying  Instructions  has  been  again  revised  with 
a  view  to  harmonizing  the  printed  instructions  furnished  to  the  sur- 
veyors with  recent  legislation  and  current  surveying  practice.  The 
use  of  iron-post  corner  monuments  adds  much  to  the  permanency 
of  the  evidence  of  the  surveys,  but  this  calls  for  little  change  in  rules 
except  to  outline  the  standard  practice.  A  growing  necessity  for 
resurveys  to  identify  and  restore  original  surveys  actually  made,  but 
poorly  monumented,  or  to  supersede  grossly  erroneous  or  fraudulent 
original  surveys — "to  properly  mark  the  boundaries  of  the  public 
land  remaining  undisposed  of" — has  demanded  a  full  discussion  of 
the  subject  in  this  revision  of  the  Manual.  The  change  from  the 
contract  system  to  the  present  system  under  which  the  public-land 
surveys  are  executed  by  a  permanent  corps  of  surveyors  employed 
by  the  General  Land  Office  has  involved  changes  in  the  administra- 
tive control  without  departing  from  previous  technical  procedure, 
and  hereafter  throughout  the  Manual  all  reference  to  administrative 
questions  will  be  found  to  be  stated  in  general  terms  in  order  to  avoid 
confusing  that  matter  with  the  purely  technical  subjects.  Modern 
surveying  practice  has  been  introduced  into  the  public-land  surveys 
as  far  as  legally  consistent  and  efficient,  which  has  prompted  a  rather 
full  instructive  treatment  of  the  subjects  of  measurements  with  long 
steel  tapes,  stadia  method  and  triangulations,  and  field  observations 
for  the  determination  of  time,  latitude  and  azimuth,  to  afford 
versatility  on  the  part  of  the  surveyor  in  adopting  methods  beet 
suited  to  the  ever-changing  conditions  under  which  his  work  must 
be  accomplished. 


20  3IANTJAL  OF  SURVEYING  INSTRUCTIONS. 

The  instructions  contained  in  this  Manual  are  to  be  observed  by 
every  surveyor  engaged  in  the  execution  of  the  public-land  surveys. 
All  other  surveyors,  including  those  who  have  at  times  been  em- 
ployed in  the  surveying  service  of  the  General  Land  Office,  should 
bear  in  mind  that  in  their  private  capacities  they  are  acting  under 
somewhat  different  rules  of  law  from  those  governing  original  sur- 
veys, and  surveyors  should  discriminate  between  the  provisions  of 
the  statute  which  control  original  surveys  and  those  which  apply  to 
the  retracement  of  lines  that  have  been  officially  established  and 
approved. 

THE   STANDARD   FIELD  TABLES. 

12.  There  has  been  published  by  the  General  Land  Office,  in  the 
shape  of  a  pocket  field  book,  a  compendium  of  tables  and  formulae 
entitled  "Standard  Field  Tables."  The  volume  embraces  the  data 
peculiarly  useful  to  surveyors  engaged  in  subdividing  the  public 
lands.  The  Standard  Field  Tables  are  issued  as  a  supplement  to 
the  Manual,  and  as  such  the  former  are  apart  of  the  latter,  with  con- 
tents as  follows: 

1.  Units  of  linear  measure,  units  of  area,  expansion  of  steel  tapes, 

and  conversion  tables;  chains  to  feet  and  feet  to  chains. 

2.  Reduction  in  latitude  to  south  boundary  of  township,  and  cor- 

rections for  convergency  within  a  township. 

3.  Traverse  table,  for  the  correction  of  random  lines. 

4.  Traverse  tables. 

5.  Correction  of  error  in  stadia  wire  interval. 

6.  Stadia  coefficients,  vertical  rod. 

7.  Natural  sines  and  cosines. 

8.  Natiiral  tangents  and  cotangents. 

9.  Logarithmic  sines,  cosines,  tangents  and  cotangents. 

10.  Logarithms  of  numbers. 

11.  Convergency  of  meridians,  and  differences  of  latitude  and  longi- 

tude. 

12.  Azimuths  of  the  tangent  to  the  parallel. 

13.  Offsets  from  the  tangent  to  the  parallel. 

14.  Azimuths  of  the  secant. 

15.  Offsets  from  the  secant  to  the  parallel. 

16.  Lengths  of  arcs  of  the  earth's  surface. 

17.  Apparent  time  of  sunrise  and  sunset. 

18.  Conversion  tables,  degrees  to  time,  and  time  to  degrees. 

19.  Sidereal  conversions,  and  reductions  to  the  local  mean  time  of 

upper  culmination  of  Polaris. 


REGULATIONS  IMPOSED  BY  LAW.  21 

20.  Mean  refractions  in  zenith  distance. 

21.  Coefficients  to  apply  to  mean  refractions  for  variations  in  ba- 

rometer and  temperature. 

22.  Coefficients  for  computing  errors  in  azimuth  due  to  small  errors 

in  declination  or  latitude. 

23.  Mean  refractions  in  polar  distance. 

24.  Trigonometric  formulas  for  the  solution  of  plane  triangles. 

25.  Trigonometric  formulas  for  the  solution  of  stadia  measurements, 

observations  for  time,  latitude  and  azimuth,  and  problems 
in  convergency. 

EPHEMERIS    OF    THE     SUN    AND     POLARIS,    AND    TABLES     OF    AZI- 
MUTHS OF  POLARIS. 

13.  The  above  title  has  been  given  to  a  second  supplement  to  the 
Manual  which  is  published  each  year,  a  convenience  which  serves 
to  supply  the  surveyors  with  all  necessary  data  relating  to  the  daily 
positions  of  the  sun  and  Polaris  without  requiring  frequent  revision 
of  the  text  of  the  Manual  or  the  Standard  Field  Tables.  As  a  supple- 
ment to  the  Manual  the  data  contained  in  the  Ephemeris  will  be 
adopted  in  preference  to  that  contained  in  other  publications  over 
which  the  General  Land  Office  has  no  control  either  as  to  accuracy 
or  fitness  for  use  in  the  public-land  surveys. 


CHAPTER  II. 

INSTRUMENTS  AND  METHODS. 

MEASUREMENTS. 

14.  The  law  prescribes  the  chain  as  the  unit  of  linear  measure  for 
the  survey  of  the  public  lands,  and  all  returns  of  measurements  are 
to  be  made  in  true  horizontal  distances,  in  miles,  chains  and  links. 
The  chain  unit  is  known  as  the  invention  of  Edmund  Gunter,  an 
English  astronomer  of  the  seventeenth  century,  and  is  especially 
convenient  in  computing  areas  in  the  unit  of  acres,  one  acre  being 
equal  to  10  square  chains. 

Units  of  linear  measure. 

1  chain  ==100  links. 

=66  feet. 
1  mile =80  chains. 
=5,280  feet. 

Units  of  area. 

1  acre=10  square  chains. 

=43,560  square  feet. 
1  square  mile =640  acres. 

15.  Each  surveyor  will   be   provided  with  a  standard  and  an 
assortment  of  1,  2,  5  or  8-chain  steel  tapes.    The  standard  tape  will 
be  employed  for  comparison  with  the  field  tapes,  in  order  that  errors 
in  the  latter  may  be  noted  and  corrected.    Before  chainmen  are 
intrusted  with  their  actual  duties  they  should  be  instructed  by  the 
chief  of  party,  and  required  to  measure  over  one  or  more  trial  lines  of 
level  and  mountainous  surface,  to  secure  accuracy  and  uniformity 
of  results. 

16.  It  is  essential  to  the  record  of  a  survey  to  state  briefly  at  the 
beginning  of  the  iield  notes,  with  every  set  of  returns,  the  general 
manner  of  making  measurements  in  the  survey,  and  as  topographical 

23 


24  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

difficulties  are  encountered  making  it  necessary  to  depart  from  the 
stated  general  method,  it  is  desirable  to  record  the  plan  of  special 
measurement  adopted.  The  field  notes  thus  exhibit  the  manner  of 
making  all  measurements,  and  the  record  should  be  such  that  another 
surveyor  retracing  any  line  can  substantially  duplicate  the  exact 
procedure  adopted  in  the  original  survey. 

The  following  paragraphs  are  illustrative  of  the  record  to  be  made 
in  the  field  notes: 

"Unless  otherwise  specified  all  measurements  are  made  with  a 
Chicago  1 -chain  steel  tape  compared  with  a  Chesterman  standard 
steel  tape  and  found  correct." 

"  Unless  otherwise  specified  all  measurements  are  made  with  a 
Lallie  2-chain  steel  tape  found  correct  by  comparison  with  a  Luf kin 
standard  steel  tape." 

•"  Unless  otherwise  specified  all  measurements  are  made  with  a 
Lufkin  steel  tape  8  chains  in  length  compared  with  a  Chesterman 
standard  steel  tape  and  found  correct.  The  measurements  are  made 
on  the  slope,  the  vertical  angle  determined,  and  the  slope  measure- 
ments properly  reduced  to  true  horizontal  distances." 

THE    LONG   STEEL  TAPE. 

17.  The  most  approved    method  of   measurement  involves  the 
use  of  steel  ribbon  tapes  from  2  to  8  chains  in  length;  in  its  use  in 
the  public-land  surveys  the  tape  is  properly  alined  and  stretched, 
and  the  measurements  are  made  on  the  slope  at  any  convenient  dis- 
tance up  to  the  length  of  the  tape  as  limited  by  the  topography .    The 
vertical  angles  of  the  lesser  slopes  are  determined  by  the  use  of 
clinometers  in  the  hands  of  the  chainmen,  while  the  vertical  angles 
of  the  particularly  sharp  slopes  are  determined  with  the  transit  oper- 
ated by  the  surveyor.    The  slope  distances  are  then  reduced  to  true 
horizontal  distances  and  the  entire  operation  suitably  recorded.     It 
is  not  considered  necessary  to  exhibit  in  the  official  field  notes  any 
but  the  true  horizontal  distances,  omitting  details,  except  where 
precise  measurements  are  made  of  various  bases  for  special  use. 

18.  The  following  is  an  example  of  both  field  and  final  record 
for  the  use  of  the  long  steel  tape  and  clinometer,  and  reductions  by 
the  use  of  the  traverse  tables  (see  Table  4,  Standard  Field  Tables): 


INSTRUMENTS  AND  METHODS. 


Field  record. 

Final  field  notes. 

Mean 
verti- 
cal 
angle. 

Dis- 
tance 
on 
slope. 

True 
horizon- 
tal dis- 
tance. 

Inter- 
mediate 
meas- 
ure- 
ment. 

Differ- 
ence in 
eleva- 
tion. 

-12** 
-17£° 

+  8T 
+19£° 
*7f1 

-6J- 

-ioi- 

-14  • 

o  • 

Chains. 

4.50 
2.20 

Chains. 

4.398 
2.098 

Chains. 
3.80 

0.00 

1.20 
1.90 

1.15 

Chains. 

-0.95 
-  .66 

-  .75 

Chains. 
10.30 

23.50 

24.70 
25.40 

32.€0 
40.00 

North,  bet.  sees.  19  and  24. 
Desc.  155  ft.  over  NW.  slope, 
through    scattering    timber 
and  dense  undergrowth. 

Dry  gulch,  course  W.;  asc.  295 
ft.  over  SW.  slope. 

Spur,  slopes  W.;  desc.  185  ft.  to 
1/4  sec.  cor.,  over  NW.slope. 
Wagon  road,  bears  E.  and  W. 
Leave  undergrowth. 

Enter  heavy  timber,  bears  N  W  . 
and  SE. 

Set  an  iron  post,  etc. 

• 

6.70 
8.00 

6.496 
7.917 

+  .75 
4-1-15 

+2.10 
+  .44 

14.70 
6.20 

14.  413 
5.835 

20.90 
3.30 

20.248 
3.270 

24.20 
8.00 

23.518 
7.949 

-0.91 

-  .66 
-1.21 

32.20 
3.70 

31.467 
3.641 

35.90 
5.00 

35.108 
4.851 

40.90 
.04 

39.  959 
.04 

40.94 

40.00 

40.00 

40.00 

19.  A  simplification  of  the  reduction  of  measurements  on  the 
slope  is  obtained  by  the  use  of  two  diagrams  constructed  on  cross- 
section  paper,  as  follows:  The  first  with  the  vertical  lines  repre- 
senting intervals  of  20  links  measurement  on  the  slope  to  2,  5  or 
8  chains  to  suit  the  length  of  tape  used ;  the  horizontal  lines  repre- 
senting the  correction  in  links  to  be  made  from  the  measurement 
on  the  slope  to  obtain  the  true  horizontal  distance;  slanting  lines 
are  drawn  to  represent  various  degrees  of  slope  scaled  to  the  proper 
55465°— 19 3 


26 


Slope 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 

5670 


Measurement    in  Chains. 

I  Z  3 


Fig.  I. 


INSTRUMENTS  AND  METHODS. 


27 


Slope  Measurement  in 

01  3 


Chains. 

A.  $  e 


WOttOn  in  Feet. 

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Fig.  2. 


Reduction  for  difference  of  elevation. 


28 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


points  for  the  correction  for  the  full  length  of  the  tape.  The  second 
diagram  is  constructed  with  the  vertical  lines  representing  similarly 
the  measurement  on  the  slope  in  the  chain  unit;  the  horizontal 
lines  in  this  diagram  representing  the  difference  in  elevation  in 
feel,  at  intervals  of  5  feet;  slanting  lines  are  drawn  to  represent  various 
degrees  of  slope  scaled  to  the  proper  points  for  the  differences  of 
elevation  for  the  full  length  of  the  tape.  (See  figs.  1  and  2.) 

20.  The  following  is  ?.n  example  of  record  for  the  use  of  the  long 
steel  tape  and  clinometer,  r.nd  reductions  by  the  use  of  the  reduction 
diagrams: 


Field  record. 


Mean 
vertical 
angle. 

Dis- 
tance 
on 
slope. 

Correo- 
iiou  to 
hori- 
zontal. 

Chains. 

0.10 
.10 

Inter- 
mediate 
meas- 
ure- 
ment. 

Differ- 
ence in 
eleva- 
tion. 

Final  field  notes. 

-12^° 
-17^° 

+  SJ° 
-H9f° 
+  7f> 

-6T 

Chains. 

4.50 

2.20 

Chains. 
3.80 

0.00 

1.20 
1.90 

1.15 

Peft, 

-  60 
-  45 

-  50 

Chain*, 

10.  30 

23.50 

24.70 
25.40 

32.60 
40.00 

North,  bet.  sees.  19  and  24. 
Desc.  155  ft.  over  NW.  slope, 
through  scattering  timber  and 
dense  undergrowth. 

Dry  gulch,  course  W.;  asc.  295 
ft.  over  SW.  slope. 

Spur,  slopes  W.;  dose.  185  ft.  to 
%  sec.  cor.,  over  NW.  slope. 
Wagon  road,  bears  E.  tmd  W. 
Leave  undergrowth. 

Enter  heavy  timber,  bears  NW. 

and  SE. 

Set  an  iron  post,  etc. 

C.70 
S.OO 

0.20 

.08 

+  50 
-f  75 

-f  140 
+  30 

14.70 

6.  20 

0.28 
.37 

20.90 
3.30 

0.65 
.03 

24.20 
8.00 

0.68 
.05 

-  60 

-  45 
-  80 

-101° 

—14  ° 

6  ° 

32.20 
3.70 

0.73 
.06 

35.90 
5.00 

0.79 
.15 

40.90 
.04 

0.94 

.00 

40.64 

40.  JO 

i 

0.94 
0.00 

INSTRUMENTS  AND  METHODS. 

21.  By  a  skillful  use  of  the  long  steel  tape  on  the  slope,  with  cor- 
rect determinations  of  the  vertical  angle,  and  proper  reductions 
from  the  slope  to  the  true  horizontal  distance,  the  surveyor  obtains 
one  of  the  most  rapid  and  reliable  methods  of  measurement.    It  IP 
essential  to  make  all  reductions  for  distance  as  the  work  progresses, 
but  the  additional  information  regarding  the  amount  of  the  ascents 
and  descents  is  readily  obtainable  from  the  record  at  the  conven- 
ience of  the  surveyor. 

STADIA   MEASUREMENTS. 

22.  Under  proper  safeguards  the  stadia  method  of  measurement 
affords  a  useful  and  reliable  means  of  overcoming  the  difficulties  of 
obtaining  correct  distances  across  water  and  over  precipitous  slopes 
that  can  not  be  reached  with  the  tape.     It  is  required  that  the  wire 
interval  or  ratio  be  determined  in  the  field  by  frequent  tests  under 
working  conditions  in  comparison  with  steel  tape  measurement, 
solving  the  formula  given  in  the  Standard  Field  Tables  (p.  221)  for 
the  value  of  the  wire  ratio  with  the  horizontal  distance  known.    The 
record  of  the  stadia  tests  should  be  given  in  the  field  notes.    It  is 
essential  to  accurate  stadia  work  that  rods  of  approved  construction 
be  used,  together  with  two  targets  and  a  properly  adjusted  rod  level 
to  secure  true  vertical  readings;  the  readings  at  all  times  must  be 
restricted  to  suitable  atmospheric  conditions  and  to  distances  per- 
mitting exact  bisections  of  the  targets.     Possible  criticism  of  the  use 
of  the  stadia  method  is  found  in  the  failure  to  observe  proper  details 
and  not  in  the  reliability  of  the  method  if  skillfully  followed. 

23*  It  is  desirable  to  state  briefly  at  the  beginning  of  the  field 
notes,  with  every  set  of  returns,  the  general  plan  of  making  stadia 
measurements.  The  following  paragraphs  are  illustrative  of  the 
character  of  such  record: 

"All  stadia  measurements  are  made  with  fixed  stadia  wires  with' a 
ratio  of  1  :  132 ±,  as  exhibited  by  the  tests  shown  in  the  field  notes; 
the  focal  constant  of  the  instrument  is  1.  2  links;  the  rod  used  is  a 
standard  Philadelphia  level  rod  graduated  to  feet  and  equipped  with 
two  targets  and  a  rod  level;  all  readings  are  made  with  a  vertical 
rod." 

'•'All  stadia  measurements  are  made  with  fixed  stadia  wires  with  a 
ratio  of  1  :  100 ±,  as  exhibited  by  the  tests  shown  in  the  field  notes; 
the  focal  constant  of  the  instrument  is  1.  2  links;  the  rod  used  is  a 
standard  Troy  level  rod  graduated  to  feet  and  equipped  with  two 
targets  and  a  rod  level:  all  readings  are  made  with  a  vertical  rod." 


30  MANUAL  OF  SURVEYING   INSTRUCTIONS. 

24.  Notation  used  in  stadia  measurements: 

Hor.  dist.:  The  true  horizontal  distance  from  the  center  of  the  in- 
strument to  the  rod. 

Diff.  elev.:  The  true  vertical  distance  from  the  height  of  the  instru- 
ment to  the  center  point  between  the  two  targets  of 
the  rod. 

"  r  " :    Vertical  rod  reading . 

"  v  " :    Observed  vertical  angle . 

"K":  The  wire  interval  or  ratio. 

"c":  Distance  from  the  center  of  the  instrument  to  the  object 
glass. 

"/":  Distance  from  the  plane  of  the  cross-wires  to  the  object  glass. 

Hor.  dist.=.£>  cos2  ^-f-(c+/)  cos  v. 

Diff.  elev.=J£>  %  sin  2v-f(c-f/)  sin  r. 


}  Diff.  elev. 


&9.3 

25.  In  Table  6,  Standard  Field  Tables,  the  natural  functions 
"cos2!'"  and  "£  sin  2u"   are  tabulated  by  intervals  of  2'  for  all 
angles  from  0°  0'  to  28°  0';  these  values  become  natural  coefficients 
of  the  rod  reading  in  the  use  of  the  vertical  rod.     In  the  same  table 
are  tabulated  the  natural  products  "  (c-f-/)  cos  v  "  and  "  (c+/)  sin  v, " 
for  three  values  of  "(c+/)"  which  may  be  considered  as  expressed 
in  either  the  link  or  foot  unit  as  convenient. 

26.  In  public-land  surveying  it  is  convenient  to  have  fixed  stadia 
wires  with  a  ratio  of  1:132,  so  that  the  sum  of  two  rod  readings  in 
feet  will  be  equivalent  to  a  ratio  of  1:66,  or  a  reduced  distance  in 
chains;  it  is  also  convenient  to  reduce  the  error  in  the  wire  interval 
to  the  error  in  10  chains,  and  to  eliminate  the  error  by  applying  to 
the  reduced  distance  the  proper  correction  taken  from  the  table 
of  proportional  parts  (Table  5,  Standard  Field  Tables). 


INSTRUMENTS  AND  METHODS.     .  oi 

27.  Example  of  test  of  stadia  wire  interval,  the  approximate 
ratio  being  1:132.  and  the  focal  constant  1.2  links: 


Field  record. 

Final  field  notes. 

Measurement  of  base  by  steel 
tape  and  clinometer. 

Vertical  rod 
reading. 

W  2W 

True 
horizontal 
distance. 

Chains. 

-4r            3.90 
-l-j°            8.00 
4-7-1°  1          2.20 

Total  base 
Focal  constant 

Chains. 

3.  888 
7.  998 
2.  180 

Feet. 
6.992 
6.998 
7.002 
6.995 
7.003 
7.004 
6.997 
6.995 
7.001 
6.998 

June  11,  1911,  1  make  the  follow- 
ing test  of  the  stadia  wire  inter- 
val: 
Horizontal  length 
of  base              =14.  066  chs. 
Mean  of  10  rod 
readings           -   6.9985ft. 
Vertical  angle  of 
of  test               -  -O0^ 
^=132.551 
Reduced  error  in 
10  chs.               -4.1  Iks. 

All  corrections  to  be  added  to 
the    distances   given   by    the 
stadia. 

-   14.066 
=      .012 

Stadia  base               =  14.  054  chs. 
"        "                   -927.  504  ft. 

Mean  rod  reading     = 
Coefficient  for  0°  10'  —  0.9999; 
0.0001X6.9985 

r  0082  r             = 

_    927.564 
T-~6TWTO~132*5pl 

Measured  base 

6'.9985Hmean  rod  readin*- 

6.9985 
.0007 

6.9978 

-14.  066  chs. 
14.  008  chs. 

13.997    ^equivalent  1:66. 
13.997  X  0.9999-  13.  9961 
(c+/)-     .012/ 

Error  in  14.  008  chs. 
Error  in  10.00  chs. 

by  stadia              -  0.058  chs. 
by  stadia              =»  0.041  chs. 

28.  The  error  of  the  wire  interval  having  been  determined  for  a 
distance  of  10  chains,  the  proportional  error  for  any  distance  from  1 
to  20  chains  may  be  taken  from  Table  5,  Standard  Field  Tables, 
thus  eliminating  all  complex  steps  from  the  ordinary  reductions 
of  field  observations. 

Emphasis  is  placed  upon  the  necessity  for  the  above  tests  for 
accurate  stadia  work,  and  attention  is  directed  to  the  probability 
that  successive  tasts  will  show  slightly  increasing  or  decreasing 
values  of  the  wire  interval.  It  is  not  considered  necessary  to  record 
in  the  official  field  notes  any  but  the  basic  elements  of  stadia  obser- 
vations, omitting  the  details  of  the  reductions. 

29.  The  following  example  of  record,  with  reductions  added,  is 


32 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


val,  ratio  1:132  with  an  error  of  4.1  links  in  10  chains,  and  focal  con- 
stant 1.2  links. 


Field  record. 

Final  field  notes. 

Chains. 

N.  0°  02'  W.,  bet.  sees.  15  and  16. 
Descend  gradually  over  mountainous 
land. 

3.194 
3.  212 

12.60 

Rim  of  canon,  bears  NW.  and  BE.; 
precipitous  descent  of  170  ft. 
Stadia  to  left  bank  of  creek:  3.194  and 
3.212ft,  —26°  44'. 
Stadia  to  right  bank  of  creek:  3.448  and 
3.432ft.,—  24°  10'. 
Stadia  to  right  rim  of  canon:  4.914  and 
4.895ft.,  -f4°58'. 

6.406X0.7976«5.109 
Error  +  .  021 
(C4-/)  cos  v  -1-  .011 

12.60                -f-5.14   chs. 

6.  406X0.  4018=2.  574  chs. 
Diff.  elev.                  =170  ft. 

=  17.74 

Left  bank  of  creek,  62  Iks.  wide,  worse 
NW. 

3.448 
3.  432 

' 

6.880X0.8324=5.727 
Error  -f  .  024 
(c-f/)  cos  v  +  .011 

12.60                +5.76  chs. 
5.14  chs. 

«18.36 

Right  bank  of  creek;  precipitous  aspect 
of  225  ft.  to  rim  of  canon. 

Width  of  creek 

4.914 

4.895 


=0.62   chs. 


9.809X0.9925=9.735 

Error  -f  .  040 

(c-f-/)  cos  v      .  012 


12.60 


4-9.79  chs. 


9. 809X0. 0863=0. 847  chs. 
-  56     ft. 
-H70     ft. 


Diflf.  elev. 


=  226     ft. 


-=22.30 


Rim  of  canon,  bears  NW,  and  SE.; 
asc.  gradually. 


30.  Attention  is  directed  to  the  fact  that  in  making  the  above 
reductions  in  the  chain  unit,  wire  ratio  1:132,  the  process  is  at  once 
resolved  into  taking  the  sum  of  the  two  rod  readings  in  feet  mul- 
tiplied by  the  proper  coefficient  for  vertical  angle,  to  which  product 
are  applied  the  corrections  for  the  error  in  the  wire  interval  and  for 
the  horizontal  value  of  the  focal  constant.  As  two  rod  readings 
should  alwavs  be  taken,  one  as  a  check  urxm  the  other,  the  entire 


INSTRUMENTS  AND  METHODS. 


33 


operation  becomes  very  simple.  It  should  also  be  noted  that  in 
computing  the  difference  of  elevation  no  correction  has  been  made 
for  the  height  of  the  instrument  above  the  ground,  nor  for  the  mean 
height  of  the  rod  reading;  these  corrections  are  compensating  and 
ordinarily  may  be  neglected,  but  in  precise  reductions  must  be 
considered.  Therefore,  in  ordinary  work  in  computing  differences 
of  elevation  by  the  stadia  method  it  is  permissible  to  neglect  the 
height  of  the  instrument  above  the  ground,  the  mean  height  of  the 
rod  reading,  the  error  in  the  wire  interval,  and  the  term  "(c-f/) 
ein  V." 

31.  Many  surveyors  prefer  the  conventional  stadia  wire  ratio  1:100 
generally  adopted  in  miscellaneous  surveying  practice,  using  a  rod 
graduated  to  feet.    With  an  instrument  so  fitted  for  public- land 
surveys,  in  which  the  chain  unit  of  horizontal  distance  is  stipulated 
by  law,  the  reduction  is  simplified  by  ascertaining  the  logarithm  of 
"IT" 

-gg-,  rod  in  feet  and  horizontal  distance  in  chains,  accomplishing 

the  reduction  of  llKr  cos2  D"  by  logarithmic  functions. 

32.  Example  of  test  of  stadia  wire  interval,  the  approximate  ratio 
being  1:100,  and  the  focal  constant  1.2  links: 


Field  record. 

Vertical  rod 
reading. 

i 
Final  field  notes. 

Measurement  of  base  by  steel 
tape  and  clinometer. 

if?1  sw 

True 
horizontal 
distance. 

Chains. 

-  3|°             6.40 
-  4|*            2.70 
+  12J°            5.20 

Total  base 
(«+/) 

Chains. 
6.  386  chs. 
2.692 
5.082 

Feet. 
9.515 
9.518 
9.522 
9.519 
9.527 
9.513 
9.521 
9.524 
9.521 
9.520 

July  7,  1915,  I  made  the  following 
test  of  the  stadia  wire  interval: 
Horizontal 
length  of  base=  14.  160     chs. 
Mean  of  ten  rod 
readings          =  9.5200ft. 
Vertical  angle  of 
test         .       =  -H°54' 
#=98.  193 

log  ^>rodinfect 
66 
and    horizon- 
tal distance  in 
chains              =  0.172637 

-  14.160 
=       .012 

Stadia  base             -  14.148chs. 
-933.768ft. 

Mean  rod  reading  = 
Coefficient  for  1°54'  =0.9989; 
0.0011X9.5200  - 

r  cos2  v= 

'•JWfe-f 

log  1T=  1.992081 
<r  66=  1.819544 

9.5200 
.0105 
9.5095 

"  —=0.172537 
66 

34 


MANUAL  OP^  SURVEYING  INSTRUCTIONS. 


33.  The  following  example  of  record,  with  reductions  added,  is 
adapted  to  the  instrument  showing  the  above  test  of  the  wire  in- 
terval, ratio  1:98.193  and  focal  constant  1.2  links. 


Field  record. 

Final  field  notes. 

Chains. 

North,  bet.  sees.  31  and  36. 
Over  level  land. 

11.20 
2l.r,o 

Commence  gradual  ascent  of  40  ft.  to 
base  of  cliff. 
Stadia  to  top  of  cliff: 
mean  8.  472ft.  ,+16°  407. 
Base  of  cliff,  bears  N.  65°  W.  and  S.  65° 
E.;  ascend  190ft.  to  top. 

log^               -  0.172537 

"  &4T2           =  0.927986 
/9.  981361 
~\9.  981361 

1.  063245 

. 

K 

nat    g^r  cos2  r=  11.568 

(c+/)  cos  r=       .  012 

14.20          +  11.58  chs. 

25.  78 

Top  of  cliff;  thence  over  level  mesa. 

logJT               =1.992081 
"      8.472      -0.927986 
"      0.2748    =9.439017 

2.359084 

Diff.  elev.=  228ft. 
To  bluff    =  40 

Cliff           =188" 

34.  Most  of  the  General  Land  Office  surveying  instruments  are 
equipped  with  fixed  stadia  wires  of  the  ratio  1:132,  which  has  been 
found  well  adapted  to  all  practical  purposes  for  which  used,  and 
enables  the  use  of  standard  double  target  level  rods  graduated  to 
feet.  A  few  instruments  have  been  provided  with  fixed  stadia  wires 
of  the  ratio  1:100,  at  special  request,  but  rods  graduated  to  links 
can  not  be  furnished  except  upon  special  order,  and  are  not  pur- 
chased because  they  are  useless  except  for  the  one  purpose.  Sur- 
veyors can  not  expect  to  accomplish  the  best  results  where  they 
graduate  their  own  rods  to  suit  a  particular  instrument  or  personal 
equation. 


INSTRUMENTS  AND  METHODS.  35 

In  authorizing  the  use  of  the  stadia  method  in  the  public-land 
surveys  it  is  not  contemplated  that  the  same  will  be  made  a  sub- 
stitute for  steel  tape  measurement  where  the  latter  is  practicable, 
but  rather  that  the  stadia  method  may  be  used  as  an  expedient  where 
natural  obstacles  are  encountered  over  which  the  distance  may  be 
more  accurately  measured  by  the  stadia  than  otherwise,  provided 
that  every  safeguard  is  duly  observed. 

TRIANGULATIONS. 

35.  In  making  all  triangulations  for  the  purpose  of  obtaining 
measurements  across  water  or  over  precipitous  slopes,  the  surveyor 
is  expected  to  exercise  his  best  judgment  in  the  selection  of  the 
measured  base,  and  he  is  required  to  adopt  the  best  possible  geo- 
metric proportions  of  the  sides  and  angles  of  the  triangle.    A  com- 
plete record  of  the  measurement  of  the  base,  the  determination  of 
the  angles,  the  location  and  direction  of  the  sides,  and  any  other 
essential  details  of  the  problem  will  be  required  in  the  field  notes, 
together  with  a  small  diagram  to  graphically  represent  the  triangu- 
lation,  but  it  is  not  considered  necessary  to  include  in  the  official 
field  notes  the  process  of  the  solution.   The  method  of  triangulation 
at  all  times  must  be  sufficiently  refined  to  produce  reliable  results, 
and  when  necessaiy  to  determine  the  value  of  an  angle  of  a  triangle 
with  a  precision  of  less  than  the  least  reading  of  the  instrument,  the 
method  of  repetitions  will  be  employed. 

36.  In  its  simplest  form  the  method  of  repeating  an  angle  consists 
in  sighting  upon  a  station,  A,  with  the  vernier  of  the  horizontal  cir- 
cle set  at  zero;  the  angle  is  then  turned  to  the  second  station,  B;  the 
lower  clamp  is  now  loosened  and  the  telescope  again  set  upon  station 
A  with  the  lower  tangent  motion  without  disturbing  the  angle  first 
turned,  after  which  the  upper  clamp  is  loosened  and  the  angle  turned 
a  second  time  to  station  B.     The  angle  is  thus  '^repeated"  two, 
three,  or  more  times,  and  finally  the  multiple  angle  is  read,  which, 
when  divided  by  the  repeating  factor,  gives  a  value  for  the  angle 
much  closer  than  the  least  reading  of  the  instrument.     For  example, 
assume  an  instrument  reading  to  single  minutes  of  arc,  and  that  a 
certain  angle  has  been  repeated  five  times  with  a  resulting  reading 
of  124°  32';  this  gives  a  value  of  24°  54'  24"  for  the  angle,  which  if 
skillfully  done  is  unquestionably  closer  than  a  single  reading.     In 
surveys  which  may  require  even  greater  precision  both  verniers  are 
read  and  the  angle  is  repeated  as  nearly  as  practicable  to  one  com- 
plete turn  of  360°,  when  both  verniers  are  again  read.   The  observer 


36 


MAXUAL  OF  SURVP;YING  INSTRUCTIONS. 


the  angle  in  the  opposite  direction,  to  eliminate  instrumental  errors, 
and  finally  takes  a  mean  of  the  resulting  four  readings,  which  is  di- 
vided by  the  proper  factor.  It  is  occasionally  necessary  in  public- 
land  surveying  to  repeat  angles  by  the  latter  method,  but  the  for- 
mer method  is  of  more  general  use  and  will  be  found  dependable 
and  quickly  executed. 

37.  The  base  lines  for  triangulations  are  to  be  carefully  measured, 
even  to  tenths  of  links  if  necessary,  and  the  sum  of  the  angles  should 
be  balanced  to  180°,  or  redetermined  if  the  disagreement  is  found  to 
exceed  V  of  arc. 

38.  The  following  examples,  with  the  reductions  added,  are  de- 
signed to  illustrate  the  form  of  record  of  triangulations  best  suited 
for  the  official  field  notes: 


(a)  Field  record. 

Final  field  notes. 

Angles. 
50°  35' 
93    20 
36    05 

Chains. 

40.00 
72.20 

S.  89°  56'  W.,  on  random  line  bet.  sees. 
19  and  30. 
Set  temp.  }  sec.  cor. 
Top  of  precipitous  bluff:  vertical  angle 
to  flag  on  random  line=—  32°  47'; 
auxiliary  flag  bears  S.  39°  21'  W.; 
from  flag  on  random  line  the  auxiliary 
flag  bears  S  3°  16'  W    12  SOchs  dist  • 

180°  00' 

Hor.  meas.  of  base  by  one  chain 
tape=12.80chs. 

all  bearings  checked  by  direct  read- 
ing of  the  solar,  and  all  angles  checked 
by  deflection: 

r»ist-1280sin  36°05' 

**/                    7 

sin  50°  35' 

log  12.  80                         =1.107210 
"  sin  36°  05'                =9.770087 

^                         7 

0.877297 
"  sin  50°  35'                =9.887926 

*!/ 

"   9.76                           =0.989371 
Dist.  bytri.                  =9.76chs. 

Dist.  on  random  line          =72.  20  chs. 

log  hor.  dist.                 =0.989371 
<P    66                             =1.819544 
"     tan  32°  47'              =9.808916 

Dist.  by  tnangulation         «>  9.  76 

81.96 
Dist.  by  return  meas.         =  2.  84 

11     415                           =2.617831 
Diff.  elev.=415  ft. 

79.12 

1.75 
6.92 

79.12 
Intersect  W.  bay.  of  Tp.,  14  Iks.  S.  of 
the  cor.  of  sees.  19,  24,  25  and  30. 
Thence 
S.  89°  58'  E.,  on  a  true  line  bet.  sees. 
19  and  30. 
Ascend  gradually  in  valley. 
Base  of  bad-land  bluff,  bears  N.  and  S.: 
precipitous  ascent  of  about  400  ft. 
Top  of  bad-land  bluff,  bears  N.  and  S.; 
thence  over  level  prairie. 

INSTRUMENTS  AND  METHODS. 


37 


(6) 


Field  record. 


Final  field  notes. 


NOTE.— Stadia  wire  ratio,  1:132.551; 
e+/)=1.2  Iks. 

9.827 
9.839 


19.666 

Error=-f.082 
.012 


=19.76 


79°  11' 
33  03 
67  46 

ISO0  W 


loe;  19.76 
"  sin  67°  46' 


'•  sin  33°  03' 
"  33.54 
Dist.  by  tri. 


1.295787 
9.966447 


1. 262^34 
9. 736692 


-  1.525542 

-  33.54  chs. 


At  the  meander  cor.  at  57.30  chs.  bet.  sees. 
16  and  17.  a  flag  on  Indian  Island  bears 
N.  18°  41'  W.;  a  point  on  a  rock  in  the 
lake  bears  S.  82°  08'  W.,  stadia  base  to 
this  point:  9.827  and  9. 839  ft.,  level, 
measured  base  impracticable;  from  point 
on  island,  flag  on  rock  in  lake  bears 
S.  14°  22'  Vvr.;  all  bearings  checked  by 
direct  reading  of  the  solar,  and  all  angles 
checked  by  deflection: 

Length  of  base  =19.76  chs. 

From  meander  cor.  to  island=- 33.54  chs. 


At  the  above  point  on  Indian  Island  from 

which  the  meander  cor.  at  57.30  chs.  bet- 

sees.  16  and  17,  bears  S.  18°  41'  E.f  33.54 

chs.  dist.:  I 
Set  a  limestone,  28  x  10  x  6  ins. ,  21  ins.  in  the 

grour  d,  for  auxiliary  meander  cor.  in  sec. 

8,  mkd.  A  M  C  on  S.  face;  from  which 
A  spruce,  14  ins.  d'am..  bears  N.  42*  °  E., 

69  Iks.  dist.,  mkd.  T67NR43WS8 

A  V  C  B  T. 
A  fir-balsam,  9 ins.  diam.,  bears  N.  14J°  W.. 

38  Iks.  dist.,  mkd.  T  67  N  R  43  W  S  8 

A  M  C  B  T. 


<O 


Field  record. 


Final  field  notes. 


Chains. 


5th  Guide  Meridian  West,  through  T. 

14  N..  between  Rs.  20  and  21  W. 
North,  bet.  sees.  13  and  18. 
Descend  225ft.  over  N  W.  slope,  through 
heavy   timber    and    dense    under- 
growth. 

Difference  between   measurement   of 
27.80  chs.,  by  two  sets  of  chainmen, 
is  4  Iks.;  position  of  middle  point 
by  1st  set =27.78  chs., 
by2d    "  =27.82    "  , 
the  mean  of  which  is 


38 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


(c)         Field  record,  con. 


Final  field  notes,  con. 


27.  SO 

The  south  shore  of  Grand  Lake,  bears 

N.  62°  E. 

and  S.  48°  W. 

Set  an  iron  post,  3  ft.  long,  1  in.  diam., 
28  ins.  in  the  ground,  for  meander 
cor.  of  frac.  sees.  13  and  18,  with  brass 

cap  mkd. 

we  ^^ 

A 

/sis  sia 

R  21  W|  R20W 

TI<fN 

1915 

from  which 

A  pine,  8  ins.  diam.,  bears  N.  842°  E., 
105  Iks.  dist.,  mkd.  T  14  N  R  20  W  S 

18MCB 

r. 

A  pine,  10  ins.  diam.,  bears  3.  26J°\V., 
49  Iks.  dist.,  mkd.  T  14  N  R  21  W  S 

13  M  C  B  T. 

AtX-  '——  =  1S°09'40"(-02") 

To  make  a  triangulation  across  the  lat  c 
I  designate  the  above  meander  ccr. 

o 
<«  £„€*$!!?:'».  81°  44'20"(-09") 

point  A  and  set  a  flag  B  at  point  fcr 
meander  cor.  on  north  shore  of  lake. 

3 

also  a  flag 

C  on  the  north  shore  which 

«  O.240*19^  80°  OG'20"(-09") 

from  point  A  bears  N.  18°  09'  38"  E.; 
the  base  PC  bears  S.  81°  14'  11"  E., 
16.427  chs.  dist.,  the  mean  by  two 

180°00'20"(-20") 

sets  of  chainmen, 

by  1st  set=16,425  chs., 

by2d   "  »  16.429    "  . 
longer  base  impracticable;  the  angle 
subtended  at  point  O=80°  OG'  11"; 

all  angles  by  three  repetitions  with 
error  of  0'  20"  balanced  to  ISO0. 

Distance  across  lake=51.92  chs. 

B 

"£%t* 

• 

JO 

/c 

(j 

/ 

5j 

/V 

ic  r"  siu  so°  °6'  ll" 

5j 

* 

log  16.  427               '      =1.215558 

* 

"  sm  80°  06'  11"      =9.993488 

V. 

/ 

^ 

1.209046 

/ 

•«    "   18°  09'  38"      -9.493710 

/ 

"        51.92                -1.715336 

/ 

4-27.80 

A 

79.72 

79.  72 

The  north  shore  of  lake,  bears  S.  82°  E. 

and  N.  75e 

W. 

INSTRUMENTS  AND  METHODS.  39 

39.  In  practical  field  work  triangulations  are  made  only  to  over- 
come physical  difficulties  of  measurement,  and  under  the  conditions 
generally  presented  a  right-angled  triangle  is  likely  to  be  less  desir- 
able than  an  oblique  triangle  as  the  latter  may  be  selected  to  fit  the 
best  topography  for  the  base  line.    A  stadia  base  may  likewise  be 
superior  to  a  measured  •  base  as,  for  example,  in  extremely  rough 
mountainous  regions  where  possibly  no  obstruction  would  interfere 
with  a  good  stadia  determination  even  though  a  steel  tape  measure- 
ment of  the  same  base  might  be  almost  impossible,  or  involve 
great  delay  and  expense.    Under  some  conditions  a  double  triangu- 
lation  by  independent  bases  may  be  highly  desirable,  one  result 
as  a  check  upon  the  other,  whereby  the  mean  of  the  two  would  be 
a  better  value  than  either  result  alone.    True  efficiency  demands  a 
choice  of  the  best  methods  to  suit  the  peculiar  conditions  encoun- 
tered in  each  circumstance,  and  this  must  be  left  to  the  judgment 
of  the  surveyor. 

The  subject  of  measurements  is  incomplete  without  a  suggestion 
that  each  surveyor  should  devise  a  system  of  signals  by  means  of 
which  numbers  and  directions  may  be  readily  communicated  from 
one  member  of  a  party  to  another;  such  signals  will  be  found  espe- 
cially useful  in  long  steel  tape  and  stadia  measurements  and 
triangulations. 

INSTRUMENTS    AND    REQUIREMENTS    AS    TO    THEIR    ADJUSTMENT. 

40.  The  direction  of  all  lines  of  the  public  land  surveys  will  be 
determined  with  reference  to  the  true  meridian  as  defined  by  the 
axis  of  the  earth 's  rotation .     N  o  departure  f ron  this  rule  is  authorized . 
Beginning  with  the  Manual  of  1890  the  use  of  the  magnetic  needle 
was  prohibited  except  in  subdividing  and  meandering,  and  then 
only  in  localities  free  from  local  attraction  and  with  the  use  of 
suitably  constructed   needle    instruments.     The  Manual   of   1894 
required  that  all  surveys  of  the  public  lands  of  the  United  States, 
embracing  all  classes  of  lines,  be  made  with  reference  to  the  true 
meridian,  independently  of  the  magnetic  needle,  and  this  pro- 
hibition against  the  use  of  the  magnetic  needle  was  even  more 
pronoiinced  in  the  Manual  of  1902.     In  the  modern  instruments  the 
length  of  the  needle  and  other  details  relating  to  its  construction  are 
sacrificed  in  favor  of  the  vastly  more  important  details  of  design  of 
the  transit  and  solar  attachment,  and  it  is  not  presumed  that  the 
needle  of  the  modern  solar  transit  will  give  results  even  as  reliable 


40  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

as  those  of  a  well-constructed  needle  compass.  Many  years*  use 
of  the  solar  transit  and  of  the  solar  compass  have  proven  that  com- 
paratively few  localities  are  free  from  some  local  magnetic  attraction. 
The  needle  has  some  value  as  a  check  and  for  approximate  reference 
purposes  under  certain  conditions,  which  need  not  be  discussed  in 
the  Manual,  but  the  use  of  the  needle  as  a  means  of  determining  the 
direction  of  lines  of  the  public- land  surveys  is  now  unqualifiedly 
prohibited. 

41.  Each  surveyor  will  be  supplied  with  one  or  more  instruments 
of  approved  construction  suited  to  the  conditions  to  be  encountered 
in  his  field  work.    It  is  considered  desirable  to  include  in  the  record 
of  every  survey,  at  the  beginning  of  the  first  book  of  field  notes  of 
every  set  of  returns,  a  description  of  the  instrument  used  and  the 
general  method  by  which  the  azimuth  determinations  were  accom- 
plished.   The  following  paragraphs  suggest  the  form  of  record  to 
be  made: 

"Survey  commenced  August  1,  1915,  and  executed  with  a  Buff 
'Rocky  Mountain  Favorite '  solar  transit  No.  9936,  1915  model, 
with  U-shaped  standards,  4J-inch  horizontal  circle,  4-inch  ver- 
tical circle,  and  improved  Smith  solar  attachment;  all  azimuth 
determinations  are  accomplished  with  the  solar  attachment  except 
the  special  observations  upon  Polaris  and  the  sun  for  meridian  upon 
which  to  test  the  solar  apparatus  as  stated  in  the  field  no  tea. " 

"Survey  commenced  July  28, 1909,  and  executed  with  a  Young  & 
Sons  mountain  transit,  No.  8070,  1907  model;  the  instrument  is 
equipped  with  a  full  vertical  circle  and  the  Smith  solar  attachment; 
unless  otherwise  specified  all  azimuth  determinations  are  accom- 
plished with  the  solar  attachment. " 

"Survey  commenced  May  7, 1906,  and  executed  with  a  Burt  solar 
compass  made  by  W.  &  L.  E.  Gurley,  1905  model;  unless  otherwise 
specified  all  azimuth  determinations  are  accomplished  with  the 
solar  compass.  The  Polaris  observations  in  camp  are  made  with  a 
Keuffel  &  Essex  mountain  transit  No.  9699,  1903  model." 

42.  The  proper  supervising  officer  will  carefully  examine  all 
instruments  to  see  that  they  are  in  first-class  condition  for  field 
work,  but  the  burden  of  the  final  test  is  placed  upon  the  surveyor 
who  uses  the  instrument,  as  in  every  case  the  approval  of  an  instru- 
ment will  be  made  conditional  upon  satisfactory  field  test,  the 
record  of  which  will  be  stated  in  the  field  notes. 

43.  The  record  of  the  field  test  of  the  instrument  should  embrace 
"a  comprehensive  statement  of  fact  as  to  date,  locality,  and  condi- 


INSTRUMENTS  AND  METHODS.  41 

tion  of  the  instrumental  adjustments.  The  data  relative  to  the 
independent  observations  for  meridian  should  be  included  in  the 
record,  and  the  functions  of  apparent  time,  latitude  and  sun' a 
declination  will  always  be  given  in  connection  with  the  meridional 
tests  of  solar  instruments.  Various  forms  of  record  will  be  found 
in  connection  with  the  examples  of  observations  and  reductions 
given  on  the  following  pages. 

44.  When  a  transit  without  solar  attachment  is  employed,  Polaris 
observations,  or  direct  altitude  observations  upon  the  sun,  necessary 
to  execute  the  work  in  accordance  with  existing  law  and  the  require- 
ments of  these  instructions  will  be  insisted  upon.     Observations 
upon  Polaris,  or  direct  altitude  observations  upon  the  sun,  at  fre- 
quent intervals,  will  be  necessary  to  secure  accuracy  in  the  pro- 
jection of  transit  reference  lines,  when  solar  apparatus  is  not  used. 
The  method  of  transferring  the  azimuth  determined  by  the  meri- 
dional observations  to  the  surveyed  lines  will  distinctly  appear  in  the 
field  notes. 

45.  Surveyors  using  instruments  with  solar  apparatus  will  be  re- 
quired to  make  azimuth  observations  on  Polaris,  or  direct  altitude 
observations  upon  the  sun,  at  the  beginning  of  every  survey,  to  test 
the  accuracy  of  the  solar  apparatus,  and  subsequent  tests  will  be 
required  at  least  at  the  beginning  of  the  subdivision  of  every  town 
ship. 

46.  A  test  at  the  conclusion  of  a  survey  is  necessary  in  order  to 
prove  the  continued  proper  projection  of  transit  lines  or  the  con- 
tinued satisfactory  adjustment  of  the  solar  apparatus  during  the 
survey.     A  book  of  field  notes  of  the  survey  of  standard  lines,  or 
of  township  exteriors,  will  therefore  show  preliminary  and  final  azi- 
muth observations  for  the  projection  of  transit  lines,  or  preliminary 
and  final  observations  and  tests  for  the  adjustment  of  the  solar  appa- 
ratus, and  intermediate  tests  to  comply  with  the  requirements  of 
the  preceding  paragraphs.     The  satisfactory  condition  of  the  solar 
apparatus  at  the  conclusion  of  the  subdivision  of  a  township  exe- 
cuted with  the  solar  apparatus  may,  if  so  desired,  be  shown  by  spe- 
cific reference  to  the  next  succeeding  test  preliminary  to  commenc- 
ing the  subdivision  of  another  township  included  in  the  same  series 
of  books  of  subdi visional  notes.     A  careful  surveyor  will  make  a 
sufficient  number  of  tests  to  satisfy  himself  at  all  times  of  the  accu- 
racy of  his  alinement,  but  it  is  not  intended  to  burden  the  surveyor 
or  the  field  notes  with  superfluous  evidence  in  this  particular 
matter. 


42  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

GENERAL   STATEMENT,   TIME,   LATITUDE   AND   AZIMUTH. 

47.  WKen  considering  the  following  treatment  of  field  methods  of 
determination  of  time,  latitude  and  azimuth,  the  surveyor  should 
bear  in  mind  that  a  small  error,  either  in  assumed  latitude  or  azi- 
muth, produces  only  a  slight  effect  in  time,  and  when  all  are  un- 
known the  order  of  sequence  in  their  determination  should  be  that 
of  time,  latitude  and  azimuth.  Time  may  be  readily  determined 
by  the  surveyor  with  an  error  not  to  exceed  10  seconds,  while  lati- 
tude and  azimuth  are  readily  determined  with  an  error  not  to  exceed 
V  OCX' ;  the  stated  limits  of  error  are  not  unreasonable  where  any  of 
the  methods  herein  described  and  authorized  are  employed ;  small 
errors  in  assumed  longitude  may  be  neglected  in  the  determination 
of  time,  latitude  and  azimuth. 

The  following  methods  are  limited  to  observations  upon  the  sun 
and  the  north  star,  Polaris,  and  are  arranged  to  facilitate  the  sur- 
veyor's work  under  all  conditions  encountered  in  the  field,  without 
involving  more  than  an  elementary  understanding  of  astronomical 
technology.  The  tables  and  formulas  published  in  the  Standard 
Field  Tables,  and  the  complete  daily  ephemeris  of  the  sun  and 
Polaris  and  the  tables  of  azimuths  of  Polaris,  published  in  the 
"Ephemeris,"  are  designed  primarily  for  the  convenience  of  the 
public-land  surveyors  in  the  field,  thus  encouraging  a  general  use 
of  approved  modern  methods,  consistent  at  all  times  with  the  sur- 
veyor's clear  understanding  of  underlying  principles  involved. 

All  reference  to  tables  and  formulas,  or  to  the  daily  functions  oJf 
the  sun  or  Polaris,  that  follow  herein,  relate  to  the  above  supple- 
ments to  the  Manual,  and  when  necessary  to  use  conventional  nota- 
tion in  the  demonstrations  that  follow,  the  same  agrees  with  that 
shown  in  detail  in  the  Standard  Field  Tables. 

With  relation  to  the  subject  of  records  of  observations  as  the  same 
should  appear  in  the  official  field  notes  of  a  survey,  it  must  be 
granted  that  it  is  absolutely  necessary  to  state  all  of  the  special  basic 
functions  of  an  observation,  but  it  is  quite  unnecessary  to  include 
the  process  of  reduction,  except  in  unusual  cases;  thus  the  field 
notes  should  be  complete  in  every  respect,  and  it  is  the  purpose  to 
insist  upon  this  requirement  without  involving  that  which  is  unes- 
sential to  the  record.  In  general  also,  no  attempt  is  warranted  by 
which  the  surveyor  may  endeavor  to  make  his  results  by  analytical 
reduction  appear  to  be  more  accurate  than  justified  by  the  refine- 
ments of  the  observation  upon  which  a  determination  is  based ;  but , 


INSTRUMENTS  AND  METHODS. 


43 


it  is  good  practice  not  to  discard,  the  various  small  elements,  fractions 
or  decimal  parts  of  the  record  value  of  a  function  until  the  result  is 
ascertained,  whereupon  the  insignificant  figures  may  be  disposed  of. 

ANALYTICAL   NOTATION,  DECLINATION  AND   REFRACTION. 

48.  7^:  The  symbol  for  approximation;  this  symbol  signifies  in- 
equality, but  it  is  used  in  a  relation  representing  an  inequality 
which  approaches  equality. 


North 
Pole 


Fig.  4. 
The  "polc-zenith-sun"  triangle  as  viewed  from  outside  of  the  celestial  sphere. 

49.  v :  Observed  vertical  angle ;  in  altitude  observations  on  the  sun, 
the  reductions  to  the  sun's  center  both  vertically  and  horizontally, 
as  well  as  instrumental  errors,  are  eliminated  by  taking  direct  and 
reversed  observations  on  the  opposite  limbs  of  the  sun,  and  the  mean 
observed  vertical  angle  to  the  sun's  center  will  be  designated  v  in  the 
notation.  In  single  observations  the  vertical  reduction  to  the  sun's 


44 


MANUAL  OF  SURVETINQ   FNSTBUCTIONS. 


center  =16';   a  refinement  is  had  by  referring  to  the  "  Epherneris  '  r 
for  the  value  of  the  sun's  seini-diaineter  for  the  date  of  observation. 

50.  h:  True  vertical  angle  to  the  sun's  center,  or  to  Polaris,  in  alti- 
tude observations,  after  correction  for  refraction:  h=v—  refraction  in 
zenith  distance;  a  refinement  is  had  in  altitude  observations  on  the 
sun  by  adding  the  value  of  the  sun's  parallax  =8/x.  9  cos  v,  opposite 
in  effect  to  refraction,  which  results  from  the  observer's  position 
above  the  center  of  the  earth. 

51.  f  :  Zeta:  true  zenith  distance  of  the  sun's  center: 


Examples  of  the  relative  use  of  r,  refraction,  parallax,  h  and 


Field  record. 


Tele- 
scope. 

Watch 
time. 

Horizontal 
angle. 

Vertical 
angle. 

Sun's 
limbs. 

Dir. 

3>*M8. 

65°    0'    0" 

25°  20'     0" 

i 

Rev. 
Mean 

3  58  48 

64    45     0 

25    31     0 

* 

3i>57™53> 

64°  52'  30"  |      25°  25'  30" 

v  =        25°  25'  30" 

Refraction^          —  2'    0" 

Parallax-          -f-  V    8" 


Ji  =       25°  23'  38" 
f  -       64°  36'  22" 

90°    0'    0" 


Final  field  notes. 


Mar.  18,  1910,  I  make 
an  altitude  obser- 
vation upon  the  sun 
for  time  and  azi- 
muth, making  two 
observations,  one 
each  with  the  tele- 
scope in  direct  and 
reversed  positions, 
observing  opposite 
limbs  of  the  sun. 

Mean  watch  time  of 
observation,  3h  57m 
53s  p.  m. 

Mean  horizontal  an- 
gle from  flag  S.  to 
sun  SW.,  64°  52' 30". 

Mean  observed  verti- 
cal angle  25°  25' 30". 


Example  of  vertical  reduction  to  the  sun's  center. 


Field  record. 


Final  field  notes. 


Sun's  lower  limb 
Redaction  to  sun's  center 

Sun's  center, 


=25°  20'    0" 
-     +16'    6" 


r     =25°  36'    6" 

Refraction     =    -  2'    0" 

Parallax     =     -f  O7    8" 


=25°  34'  14" 
=.64°  25'  46" 


909    <Y    0" 


Mar.  IS,  1910,  I  make 
an  altitude  obser- 
vation upon  the  sun 
for  timej  observing 
the  sun's  lower  limb 
only;  failing  to  ob- 
serve the  sun's  up- 
per limb  in  the  re- 
versal of  the  transit 
on  account  of  clouds. 

Watch  time  of  obser- 
vation, 3h  56m  58s 
p.m. 

Observed  vertical  an- 
gle to  sun's  lower 
limb,  25°  20'  0",  cor- 
rected to  the  sun's 
center =25°  36'  6". 


INSTRUMENTS  AND  METHODS.  45 

52.  <f>:  Phi:  Latitude  of  the  station  of  observation. 

53.  X:  Lambda:  Longitude  of  the  station  of  observation. 

54.  6:  Delta:  Declination  of  the  sun  or  Polaris;  to  be  taken  from 
the  Ephemeris  for  the  date  of  observation;  the  declination  of  the 
sun  is  to  be  corrected  in  hourly  difference  to  the  longitude  of  the 
station  and  to  the  time  of  observation;  north  declinations  are  treated 
as  positive  and  south  declinations  as  negative;  a  northerly  hourly 
motion  is  treated  as  positive  and  a  southerly  hourly  motion  is  treated 
as  negative;  in  the  use  of  the  solar  attachment  the  decimation  of 
the  sun  is  to  be  corrected  for  refraction  in  polar  distance,  always 
north. 

Examples  of  computation  of  the  sun's  declination. 

(a)  It  is  desired  to  compute  the  value  of  the  sun's  declination  for 
the  above  altitude  observation  upon  the  sun  for  time  and  azimuth. 
Longitude  of  the  station  of  observation,  511  8m  W.;  apparent  time  of 
observation,  3h  42m  p.  m.: 
Declination  of  the  sun  at  Greenwich  apparent  noon 

Mar.  18,  1910  =1°  IV    3"  S. 

Difference  in  time  from  Greenwich  apparent  noon 

to  apparent  time  of  observation: 
For  longitude    ==     5h    8m 
Fortune,  p.  m.  =  -f3   42 

8.83h=     8h  50m 

Hourly  difference  in  declination=-f-59//.28 
Difference  in  declination  from  Greenwich  apparent 
noon  to  apparent  time  of  observation: 

8.83X59.28=523"  =        8'  43"  N. 


True  declination  of  the  sun  .    1°    2'  20"  S. 


(6)  It  is  desired  to  prepare,  by  computation,  a  table  of  hourly 
declinations  of  the  sun,  corrected  for  refraction  in  polar  distance, 
for  use  with  the  solar  attachment,  for  a  date  March  14,  1912,  and  for 
a  station  in  latitude  33°  HX  N.,  and  longitude  7h  47m  W. 


46 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


2°  33'  28".6  S.  =Declination  of  the  sun  at  Greenwich  apparent 

noon,  Mar.  14,  1912. 

Difference  in  time  from  Greenwich  apparent  noon 
to  7  a.  m.,  local  app.  time: 

For  longitude  =         7h  47m 

For  time,  a.  m.,  12h~7h  Om  =  (-)  j>  _  0_ 

2.78h=        2h  47m 

Hourly  difference  in  declinations  =-f-59//.  2. 
2'  44".5  N.==  Difference  in  declination  from  Greenwich  apparent 
noon  to  7  a.  m.,  local  apparent  time:  2.78X59.2= 
164".5. 


2°  30'  44".  1  S.  =True  declination  of  the  sun,  7  a.  m.,  local  apparent 
time. 


Local  apparent  time. 

True  declina- 
tion. 

Refraction. 

Declination 
setting. 

7  a  in 

2°  30'  44"  S 

2'  41"  N. 

2°  28'    3"  S 

7i... 

2    30    14 

1    48 

2    28   26 

S.  . 

2    29   45 

1    22 

2    28   23 

9  

2    23    46 

0   58 

2    27    48 

10  

2    27    47 

0    47 

2    27     0 

11  a  m 

2    25    48 

0   43 

2    26     5 

Noon  

2    25    49 

0   41 

2    25     8 

1  D.  m  .  . 

2    24    50 

0    43 

2    24     7 

2.  ... 

2    23    51 

0   47 

2    23     4 

3      ..  . 

2    22   52 

0   58 

2    21    54 

4 

2    21    53 

1    22 

2    20   31 

4-K.           .... 

2    21    23 

1    48 

2    19   35 

5  p.  m  

2    20   54 

2    41 

2    18    13 

(c)  It  is  desired  to  prepare,  by  computation,  a  table  of  hourly 
declinations  of  the  sun,  corrected  for  refraction  in  polar  distance,  for 
use  with  the  solar  attachment,  for  a  date  August  12,  1912,  and  for  a 
station  in  latitude  47°  1(X  N.,  and  longitude  7h  24m  W. 
15°  1'  6"  N.= Declination  of  the  sun  at  Greenwich  apparent  noon, 

Aug.  12,  1912. 
Difference  in  time  from  Greenwich  apparent  noon  to 
6  a.  m.,  local  app.  time: 
For  longitude=        7h  24m 
Fortune  a.m., 

12h-6h  Qm==(_)6       Q 

1.4h=        lh  24m 

Hourly  difference  in  declination——  45". 1. 
lx  3"  S.= Difference  in  declination  from  Greenwich  apparent 
noon  to  6  a.  m.,  local  apparent  time:  1.4X45.1=63//. 
15°  0'  3"  N.=True  declination  of  the  sun,  6  a.  m.,  local  apparent 
time. 


INSTRUMENTS  AND  METHODS. 


47 


Local  apparent  time. 

True  declina- 
tion. 

Refrac- 
tion. 

Declination 
setting. 

6  a  m 

15°  0'  3"N 

3'  29"  N 

15°  3'  32"  N 

6i.  . 

14  59  40 

2  22 

15   2   2 

Y" 

14  59  18 

1  46 

15   1   4 

8  . 

14  58  33 

1   9 

14  59  42 

9 

14  57  48 

0  5'! 

14  58  40 

10.. 

14  57   3 

0  42 

14  57  45 

11  a  m 

14  56  18 

0  39 

14  56  57 

Noon....       

14  55  33 

0  37 

14  56  10 

1  p  rn. 

14  54  48 

0  39 

14  55  27 

14  54   3 

0  42 

14  54  45 

3 

14  53  18 

0  52 

14  54  10 

4  

14  52  33 

1   9 

14  53  42 

5 

14  51  48 

1  46 

14  53  34 

5V  .           .  . 

14  51  26 

2  22 

14  53  48 

6  p.  nu. 

14  51   3 

3  29 

14  54  32 

(d)  A  graphic  method  for  ascertaining  the  changing  declinations 
of  the  sun,  corrected  for  refraction  in  polar  distance,  for  use  with  the 
solar  attachment,  is  obtained  by  the  use  of  a  diagram  constructed  on 
cross-section  paper  for  each  date,  as  follows: 

The  horizontal  lines  may  be  used  to  represent  each  hour  of  the  day, 
and  the  vertical  lines  may  represent  intervals  of  V  in  declination.  It 
is  convenient  to  use  the  right-hand  side  of  the  sheet  to  represent  N., 
and  the  left-hand  side  of  the  sheet  to  represent  S.,  or  to  have  N. 
declinations  increase  numerically  to  the  right-hand  side  of  the  sheet, 
and  S.  declinations  increase  numerically  to  the  left-hand  side  of 
the  sheet.  The  vertical  lines  are  numbered  to  suit  the  range  of 
declination  of  the  sun  for  the  date.  Two  points  are  marked  on  the 
diagram  to  agree  with  the  true  declination  of  the  sun;  the  first  point 
is  marked  with  the  argument  of  declination  agreeing  with  the 
declination  of  the  sun  taken  from  the  Ephemeris  for  Greenwich 
apparent  noon  and  with  the  argument  of  time  agreeing  with  the  local 
apparent  time  corresponding  to  Greenwich  noon ;  the  second  point  is 
marked  agreeing  with  the  proper  declination  and  time  10  hours  later; 
the  straight  line  determined  by  the  two  points  agrees  with  the  sun's 
true  declination  for  the  date  for  the  local  apparent  time .  The  proper 
refractions  in  polar  distance  are  then  scaled  from  the  straight  line 
to  the  N.  for  each  tabulated  refraction,  a.  m.  and  p.  m.,  taken  from 
Table  23,  Standard  Field  Tables,  appropriate  to  the  latitude  of 
observation  and  declination  of  the  sun;  the  locus  of  the  latter 
points  is  a  smooth  curve  representing  graphically  the  declinations 
of  the  sun,  corrected  for  refraction  in  polar  distance,  for  use  with  the 
solar  attachment.  The  scale  of  the  refractions  must  equal  the  scale 
of  the  intervals  of  lx  in  declination,  and  the  refractions  are  laid  off 
along  or  parallel  to  the  horizontal  lines  and  not  normal  to  the  line  of 


48 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


true  declination.  At  any  time  throughout  the  day  the  proper 
declination  for  use  with  the  solar  attachment  is  obtained  by  reference 
to  the  curve  at  the  point  corresponding  to  the  time  of  observation. 
To  obtain  any  true  value  of  the  sun's  declination  for  use  in  the 
reduction  of  altitude  observations  reference  may  be  made  to  the  straight 
line  of  true  declination  at  the  point  corresponding  to  the  time  of 
observation. 

The  advantage  of  the  diagram  method  is  found  in  the  practical 
elimination  of  errors  of  computation,  and  the  ease  with  which  it  is 
checked,  together  with  the  fact  that  in  the  use  of  the  diagram  actual 
values  are  obtained  at  any  time  without  any  process  of  interpolation . 

The  following  diagrams  have  been  prepared  to  illustrate  the 
method: 

DIAGRAM  OF  THE  SUN'S  DECLINATIONS. 

Date,  Mar.  20,  1912. 
Station:  Lat.=37°  307  N. 
Long.=7h30"1W. 
Declination. 

Greenwich  noon=0°  11'  14"  S.=4h  30»  a.  m. 
Diff.  10h,  +593"=      Q9  53    N. 

0°01/21//S.=2h  30m  p.  m. 


5 
6 
7 
8 
9 
10 
II 
Noon 
1 
2 
3 

S 

PM£ 

3 

\ 

\ 

\ 

I 

\ 

\ 

\ 

\ 

N 

\ 

\ 

S 

\ 

\ 

\ 

\ 

-^ 

\ 

\ 

X 

s 

\ 

\ 

\ 

INSTRUMENTS  AND  METHODS. 

DIAGRAM  OF  THE  SUN'S  DECLINATIONS. 

Date,  Sept.  23,  1913. 
Station:  Lat.=47°  3(K  N. 
Long.==6h  18*  W. 

Greenwich  noon=0°  03'  55"  N.=5h  42™  a,  m. 
Diff.  10h,  -585"=       9  45    S. 

Q°05/50//S.=3h  42»  p.  m. 

^  :S    * 

iCO^^OiO^       CO<M--§*^^><f-l/) 


49 


AJB4 

S 
6 
7 

8 
9 

JO 
11 
Noon 

2 

3 
4 
5 
P.M.  6 

/ 

/ 

3 

x 

/ 

/• 

/ 

^^ 

•^ 

/ 

S 

/^^ 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

/ 

7 

/ 

1 

/ 

/ 

V 

/ 

Fig.6. 

55.  A:  Azimuth  angle  from  the  true  meridian  to  Polaris,  or  to  the 
sun's  center;  in  the  following  analytical  examples  A  is  referred  to 
the  north  point  unless  otherwise  noted,  and  the  reductions  are  sym- 
metrical either  east  or  west  of  the  meridian;  all  determinations  for 
azimuth  imply  the  recording  of  horizontal  angles  from  a  fixed  refer- 
ence point  to  Polaris  or  to  the  sun,  or  that  a  point  has  been  marked 
on  the  ground  to  define  the  direction  of  observation;  the  mean 
horizontal  angle  in  the  first  case,  or  the  mean  point  in  direction  in 
the  second  instance,  being  used. 


50  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

In  the  first  of  the  foregoing  examples  of  the  relative  use  of  v,  h 
and  f,  is  shown  the  record  of  certain  observed  horizontal  angles 
from  a  fixed  reference  point  to  the  sun's  limbs,  and  now  for  the  pur- 
pose of  clearly  stating  the  use  of  the  notation  A,  the  final  reduction 
of  that  observation  is  here  anticipated,  in  which  the  following  result 

is  obtained: 

Sun's  azimuth. 

Referred  to  the  N.  point,  A=N.  114°  07'  28"  W. 
Referred  to  the  S.  point,  A=S.  65°  52'  32*  W. 
Recorded  mean  horizontal 

angle  from  flag  S.  to  the 

sun  SW =S.  64°  52'  30"  W. 

True  bearing  of  flag =S.  1°  OP  02"  W. 

In  general  in  altitude  observations  upon  the  sun  it  is  convenient 
to  record  horizontal  angles  from  a  fixed  reference  point  to  the  sun's 
limbs;  this  method  is  preferable  in  view  of  the  rapid  motion  of  the 
sun  and  the  advantage  of  minimizing  the  period  of  the  observation. 
In  observations  upon  Polaris  the  same  method  is  often  convenient, 
and  at  other  times  it  may  be  more  convenient  to  mark  points  upon 
the  ground  to  define  the  direction  of  observation,  taking  a  proper 
mean  of  the  several  points  to  define  the  true  line  of  sight  to  Polaris. 

Under  ad  verse  conditions  an  altitude  observation  upon  the  sun 
for  azimuth  may  fail  in  the  reversal  of  the  transit  on  account  of 
clouds  or  error  in  reading  one  of  the  angles  of  a  series  of  observa- 
tions, in  which  case  it  may  be  desirable  to  reduce  the  single  observa- 
tion upon  the  sun's  limbs  to  equivalent  corrected  readings  to  the 
sun's  center.  In  single  observations  on  the  sun,  the  reduction  to 

16' 
the  sun's  center  in  azimuth  == ;  a  refinement  in  the  value  of  the 

sun's  semi-idiameter  is  had  by  referring  to  the  Ephemeris  for  the  date 
of  observation. 

An  example  of  reduction  to  the  sun's  center  in  both  vertical  and 
horizontal  angles  follows: 


INSTRUMENTS  AND  METHODS. 


51 


Field  record. 


Q—  Vertical  angle  to  sun's 

lower  limb  =25°  20'  00" 

Sun's  semi-diameter  for  re- 
duction to  center  «  +16'  06" 


Sun's  center,  v  —25°  36'  06" 

Hor.  ande  from  flag  S.  to 

sun's  right  limb,  SW.      »65°  00'  00" 
Reduction  to  sun's  cen- 

ter, 

-tfi  -        ^'  54" 


Hor.  angle  from  flag  S.  to 
sun's  center,  SW.  -64°  42'  06" 


Final  field  notes. 


Mar.  IS,  1910,  I  make  an  altitude  observa- 
tion upon  the  sun  for  azimuth,  observ- 
ing the  sun's  lower  and  right  limbs  only; 
failing  to  observe  the  sun's  upper  and 
left  limbs  in  the  reversal  of  the  transit  on 
account  of  clouds: 

Apparent  time  of  observation,  3h  42m  p.  m. 

Observed  vertical  angle  to  sun's  lower 
limb,  25°  20'  00",  corrected  to  the  sun's 
center=25°  36'  06". 

Observed  horizontal  angle  to  sun's  right 
limb  from  flag  S.  to  sun  SW.,  65°  00'  00", 
corrected  to  the  sun's  centor«»640  42'  06". 


56.  Tables  of  mean  refractions  both  in  zenith  and  polar  distance 
appear  in  the  Standard  Field  Tables,  arranged  to  meet  the  require- 
ments of  field  use;  see  Tables  20  and  23.    A  table  of  coefficients  to 
apply  to  mean  refractions  in  zenith  or  polar  distance  for  variations 
in  atmospheric  pressure  and  temperature  to  obtain  true  values  of 
refractions  is  given  to  meet  occasional  necessity  for  its  use,  see 
Table  21.    In  the  absence  of  a  barometric  instrument  to  determine 
the  atmospheric  pressure,  the  argument  "  approximate  elevation 
above  sea  level"  may  usually  be  safely  substituted.    The  differ- 
ences between  the  true  and  the  tabulated  refractions  are  generally 
small  and  negligible  excepting  for  the  combined  effect  of  low  appar- 
ent altitude  of  observation  with  great  elevation  above  sea  level  or 
extremes    of  temperature.    The  following  example  of  reduction 
illustrates  the  method  to  be  employed  in  all  reductions  from  the 
tabulated  refractions: 

Tabulated  refraction  =6'  45//=6/.75;  elevation  above  sea  level 
*=10,000  feet,  for  which  elevation  the  coefficient  is  0.70;  tempera- 
ture at  the  time  of  observation  =82°  F.,  for  which  temperature  the 
coefficient  is  0.94;  true  refraction  =0.70X0.94X6/.75=4/.44=4/26". 

TIME. 

57.  The  element  of  time  enters  into  all  azimuth  determinations 
to  such  an  extent  that  the  surveyor  should  be  able  to  arrive  at  the 
exact  apparent  time  of  all  observations  upon  the  sun  and  the  exact 
local  mean  time  of  all  observations  upon  Polaris.    The  sun's  declina- 
tion varies  with  the  apparent  time  and  the  longitude  west  from 


52  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

Greenwich,  and  enters  directly  into  all  observations  upon  the  sun 
for  azimuth;  thus  the  apparent  time  and  longitude  should  be  known 
to  a  degree  of  accuracy  commensurate  with  the  refinement  necessary 
in  computing  the  sun's  declination.  The  azimuth  of  Polaris  varies 
with  the  local  mean  time  of  observation,  which  must  be  known  to  a 
degree  of  accuracy  consistent  with  the  result  wanted  in  the  deter- 
mination of  the  true  meridian.  In  observations  upon  Polaris  at 
elongation  precision  in  local  mean  time  is  unnecessary,  but  in  hour 
angle  observations  upon  Polaris  it  will  be  noted  that  at  upper  or 
lower  culmination,  in  latitude  40°  for  example,  Polaris  varies  V  in 
azimuth  in  about  2.5  minutes  of  time;  this  interval  of  time  slowly 
increases  toward  elongation  and  in  the  latter  position  more  than 
30  minutes  of  time  are  required  for  a  change  of  1'  in  azimuth. 

68.  Conversion  of  standard  time  into  local  mean  time:  watch  read- 
ing db  watch  error  in  standard  time  by  comparison  ±  correction  for 
longitude;  the  correction  for  longitude  is  additive  east  and  sub- 
tractive  west  of  the  standard  meridian  of  the  time  belt;  the  con- 
version table  " degrees  to  time"  (Table  18,  Standard  Field  Tables) 
is  convenient  in  this  reduction. 

Example  of  conversion  of  standard  time  into  local  mean  time', 
longitude  77°  01'  37".5  W. : 

Watch  time  of  observation  =6h  26m  40s  p.  m. 

Watch  slow  of  75th  meridian  standard  time  by 

comparison  with  a  standard  clock  =     -j-lm  22s 

Correction  for  longitude  of  station 

(77°  01'  37".5  W.=5h  08m  06.5")  =     -8"*  06s 

Local  mean  time  of  observation  =6h    19m  56s  p.  ncu 

59.  Conversion  of  apparent  time  into  local  mean  time:  apparent 
time  of  observation  ±  the  equation  of  time ;  the  equation  of  time  is 
to  be  taken  from  the  Ephemeris  for  the  date  of  observation  and  cor- 
rected for  the  longitude  and  time  of  observation,  conveniently 
interpolated  as  the  interval  from  Greenwich  noon  to  the  time  of 
observation;  the  watch  error  in  local  mean  time  is  then  found  by 
taking  the  difference  between  the  watch  reading  at  the  epoch  of  the 
observation  and  the  reduced  local  mean  time  of  observation. 

Example  of  conversion  of  apparent  time  into  local  mean  time; 
longitude  77°  01/37//.5W.: 


INSTRUMENTS  AND  METHODS.  ;>o 

Mar.  18,  1910,  apparent  time  of  altitude  observa- 
tion upon  sun  =3h  42m     11s     p.  m. 

Equation  of  time,  Greenwich  ap- 
parent noon  +8m  23.4" 

Interpolation  for  longitude  of  station 
5h  08m  W.,  and  time  of  observation 
3h  42m,  p.  m.,  8h  50m  after  Green- 
wich noon,  or  8.83/24  of  change 
(17.64s)  in  24  hours  =  —  6.  59 


Equation  of  time  -j-8m  16.  9s       -f  8m  17s 


Local  mean  time  of  observation  — 3h  50m  28s 

Watch  time  of  observation  =3h  57m  53s 


Watch  fast  of  local  moan  time  =         7m  25s 


TIME  IN  ITS   RELATION  TO  POLARIS  OBSERVATIONS. 

60.  Polaris,  a  star  of  the  second  magnitude,  occupies  a  position 
in  the  northern  heavens  a  little  more  than  1°  from  a  line  defined  by 
the  axis  of  the  earth's  rotation,  and  on  account  of  its  brightness  and 
proximity  to  the  polar  axis  it  ranks  to  the  surveyor  as  the  most  useful 
circtimpolar  star.  It  will  be  assumed  that  the  surveyor  has  learned 
how  to  identify  the  north  star  among  its  associates  in  the  clear  starlit 
heavens,  especially  with  reference  to  the  * '  pointers ' '  in  the  con- 
stellation of  the  "  Great  Bear,"  which  is  popularly  called  the  "  Dip- 
per." Polaris  (ex  Ursse  Minoris)  is  nearly  on  a  line  (or  great  circle) 
determined  by  the  pole  and  the  star  ' '  6  Cassiopeiae, ' '  and  both  stars 
are  located  in  the  same  direction  from  the  pole.  The  same  line  (or 
great  circle)  passes  near  the  star  "  f  Ursse  Majoris  "  (another  star  of 
the  "Dipper"),  but  the  latter  star  is  located  on  the  opposite  side  of 
the  pole.  The  surveyor  may  note  the  relative  position  of  the  three 
stars  aforementioned,  if  it  is  a  clear  night,  and  this  will  give  an  im- 
mediate indication  of  the  approximate  position  of  Polaris  in  its  di- 
urnal circle  at  such  time  of  observation.  The  novice  should  secure 
field  demonstration  in  these  details  from  an  experienced  observer. 
The  three  stars  named  are  all  of  about  the  same  brightness.  In- 
structions will  follow  (sec.  99)  regarding  the  positive  identification 
of  Polaris  by  instrumental  methods  during  the  twilight  period,  be- 
fore the  star  is  visible  to  the  naked  eye,  and  the  same  process  may 


54  MANUAL,  OF  suK\i:ri:\G  J.N> 'i  iu"< .TIONS. 


f  Star  Magnitudes 

i*   *    *     * 

I?     3     4     S 

^Meridian 

*''   \ 

/  v 


rt  ^        .v.  Polaris 
&       x-  'JSPC 
X' ' '  5  /> rra e  A'or/A  Po/e 

/          \ 


NAKED-EYE   IDENTIFICATION    OF   POLAKIS. 

About  noon  March  23rd. 
About  6  a.  m.  June  22nd. 
About  midnight  September  22nd. 
About  6  p.  m.  December  22nd. 


INSTRUMENTS  AND  METHODS.  55 

be  employed  for  verification  of  night  observations,  if  there  should 
be  any  doubt  as  in  case  the  neighboring  constellations  are  obscured 
by  clouds. 

A  skillful  surveyor  can  readily  observe  Polaris  at  sunset  or  sunrise 
without  artificial  illumination,  and  with  a  very  clear  atmosphere 
can  perform  the  observation  when  the  sun  is  as  much  as  20  or  30 
minutes  above  the  horizon .  At  any  time  that  Polaris  is  visible  any 
one  of  the  various  methods  of  Polaris  observation  for  meridian, 
properly  followed,  is  superior  to  any  form  of  observation  upon  the 
sun  for  the  same  purpose.  In  general,  in  public-land  surveying, 
the  best  of  all  practices  is  found  in  the  proper  use  of  a  solar  instru- 
ment adjusted  to  the  true  meridian  as  established  by  Polaris  obser- 
vation. 

Polaris  has  a  diurnal  circle  about  the  earth's  polar  axis  similar  to 
the  diurnal  circle  of  other  stars,  though  Polaris  has  the  smallest  circle 
of  any  naked-eye  star.  The  daily  circuit  of  Polaris  is  covered  in  one 
sidereal  day  of  24  sidereal  hours,  or  an  equivalent  of  23  hours  56 
minutes  4.09  seconds  of  mean  solar  time.  In  its  diurnal  circle  Polaris 
crosses  the  meridian  twice,  once  at  upper  culmination,  or  above  the 
polar  axis,  and  once  at  lower  culmination,  or  below  the  polar  axis. 

The  direction  of  the  apparent  motion  of  Polaris  is  suggested  by  the 
following  diagram: 


w.f. 


The  pointings  of  the  arrows  on  the  above  circle  indicate  the  direc- 
tion of  the  apparent  motion  of  Polaris  in  its  diurnal  path,  while  the 
pointings  of  the  arrows  on  the  lines  tangent  to  the  circle  show  the 
direction  of  travel  at  the  epochs  of  culmination  and  elongation.  If 
the  surveyor  has  any  doubt  in  regard  to  the  quadrant  occupied  by 
Polaris  in  its  diurnal  circle  at  the  time  of  an  observation,  he  may  set 
the  intersection  of  the  telescope  cross-wires  exactly  upon  the  star, 
then,  without  moving  the  instrument,  note  the  direction  of  the  star's 
motion  and  compare  with  the  diagram. 


56  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

The  position  of  Polaris  in  its  diurnal  circle  at  any  time  may  be 
determined  by  reference  to  the  mean  time  interval  from  upper  cul- 
mination to  any  observed  position  west  of  the  meridian,  or  by  refer- 
ence to  the  mean  time  interval  from  any  observed  position  east  of  the 
meridian  to  the  succeeding  upper  culmination. 

61.  The  Greenwich  mean  time  of  upper  culmination  of  Polaris  is 
tabulated  in  the  Epheraeris  for  every  day  in  the  year,  arranged  for 
the  ordinary  civil  date,  a.  m.  or  p.  m. 

62.  Local  mean  time  of  upper  culmination  of  Polaris:  the  Green- 
wich mean  time  of  upper  culmination  of  Polaris  is  to  be  taken  from 
the  Ephemeris  for  the  date  of  observation;  the  amount  to  be  subtracted 
from  the  Greenwich  mean  time  of  upper  culmination  of  Polaris 
to  obtain  the  local  mean  time  of  upper  culmination,  in  which  the 
argument  is  the  longitude  west  from  Greenwich,  is  obtained  from 
the  table  of  sidereal  conversions  without  computation;  see  Table  19, 
Standard  Field  Tables. 

Example  of  reduction  from  the  Greenwich  mean  time  of  upper 
culmination  of  Polaris  to  the  local  mean  time  of  upper  culmination 
of  Polaris,  longitude  111°  15'  W.: 

Aug.  12,  1910,  Gr.  U.  C.  of  Polaris=4h  08.3m  a.  m. 
Red.  to  long.  111°  15'  W.,  lm  33s   =  -  1.2 

L.  M.  T.  of  U.  C.  of  Polaris  =4h  07. lm  a.  m. 

63.  The  Greenwich  mean  time  of  elongation  of  Polaris,  latitude 
40°,  is  tabulated  in  the  Ephemeris  for  every  day  in  the  year,  arranged 
for  the  ordinary  civil  date,  a.  m.  or  p.  m. 

64.  Local  mean  time  of  elongation  of  Polaris:  the  mea'n  time  of 
elongation  of  Polaris,  Greenwich  meridian,  latitude  40°,  is  to  be 
taken  from  the  Ephemeris  for  the  date  of  observation:  the  amount 
to  be  subtracted  from  the  mean  time  of  elongation  of  Polaris,  Green- 
wich meridian,  latitude  40°,  to  obtain  the  mean  time  of  elongation 
of  Polaris,  local  meridian,  latitude  40°,  in  which  the  argument  is  the 
longitude  west  from  Greenwich,  is  obtained  from  the  table  of  side- 
real conversions  (Table  19,  Standard  Field  Tables)  without  compu- 
tation.   The  amount  to  apply  to  the  local  mean  time  of  elongation 
of  Polaris  latitude  40°  to  obtain  the  local  mean  time  of  elongation  of 
Polaris  at  the  latitude  of  observation  is  tabulated  in  the  Ephemeris 
in  connection  with  the  table  of  azimuths  of  Polaris  at  elongation. 

Examples  of  reduction  from  the  Greenwich  mean  time  of  elonga- 
tion of  Polaris,  latitude  40°,  to  the  local  mean  time  of  elongation  of 
Polaris,  latitude  64°  307  N.,  and  longitude  146°  30'  W.: 


INSTRUMENTS  AND  METHODS.  57 


EASTERN  ELONGATION. 


Sepfc.  9,  1910,  Gr.  E.  E.  of  Polaris,  Lat.  40°=8h  19.6m  p.  m. 
Red.  to  long.  146°  3(X  W.,  lm  36s  =  -  1.6 

Red.  to  lat.  64°  3(X  N.  =  +  5.8 


L.  M.  T.  of  E.  E.  of  Polaris  8h     23.8m  p.  m. 


WESTEEN  ELONGATION,  SAME  STATION. 


Oct.  16,  1910,  Gr.  W.E.  of  Polaris,  lat.  40°=5h    48. 5m  a.  m. 
Red.  to  long.  146°  30'  W.,  lm  368  -  1. 6 

Red.  to  lat.  64°  30'  N.  =     -  5. 8 


L.  M.  T.  of  W.  E.  of  Polaris  *=&    41.  lm  a.  m. 

65.  Conversion  of  a  mean  time  interval  into  a  sidereal  time  inter- 
val,  or  vice  versa:  The  amount  to  apply  tp  one  time  interval  to  obtain 
the  other  time  interval  is  found  in  the  table  of  sidereal  conversions 
(Table  19,  Standard  Field  Tables)  without  computation. 

Example  of  conversion  of  a  mean  time  interval  into  a  sidereal 
time  interval: 

Mean  time  hour  angle  of  Polaris  for  an  assumed  obser- 
vation in  Alaska  =  7h  32. 6m 

«     7h  32m  36" 
Conversion  into  equivalent  sidereal  hour  angle  =    4- .  1   . 14? 

Sidereal  hour  angle  «     7h  S38  50" 

7h  =105° 
33m=    8°  15' 
50"  =         12X  30// 

'    =113°27/30// 


66.  Hour  angles  of  Polaris:  a  mean  time  hour  angle  of  Polaris 
west  of  the  meridian  is  the  mean  time  interval  from  the  local  mean 
time  of  the  last  preceding  upper  culmination  to  the  local  mean  time 
of  observation  of  Polaris;  a  mean  time  hour  angle  of  Polaris  east  of  the 
meridian  is  the  mean  time  interval  from  the  local  mean  time  of  obr 
servation  to  the  local  mean  time  of  the  next  succeeding  upper  cul- 
mination of  Polaris. 

The  above  application  of  the  term  "hour  angle"  is  a  departure 
from  conventional  usage,  which  has  been  employed  in  order  to  sim- 
55465° — 19 5 


58  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

plify  the  text.  By  this  means  one  confusing  step  in  the  problem 
relating  to  hour  angles  for  positions  of  Polaris  east  of  the  meridian  is 
avoided.  Polaris  crosses  the  meridian  at  lower  culmination  at  an 
hour  angle  of  llh  58m  02s,  and  in  the  arrangement  of  the  various 
examples,  the  observations  west  of  the  meridian  have  been  referred 
to  the  last  preceding  upper  culmination,  and  those  east  of  the  merid- 
ian have  been  referred  to  the  next  succeeding  upper  culmination, 
thus  avoiding  the  introduction  of  any  hour  angles  exceeding  1  lh  58m 
02". 

Examples  of  computing  hour  aiiglos  of  Polaris;   all  taken  out  for 
longitude  117°  15'  W.: 

West  of  the  meridian,  p.  in.  obsn.,  U.  C.  -in  p.  m. 


L.  M.  T.  of  obsn.,  Feb.  18,  1911  =5h  20.  lm  p.  m. 

Gr.  U.  C.  same  date          =3h    36.  5m  p.  m. 

Red.  to  long.  117°  15'  W.=     -  1.3  =3   35.2    p.  m. 

Hour  angle  of  Polaris,  west  =lh  44.  9m 

West  of  the  meridian,  p.  m.  obsn.,  U.  C.  in  a.  m. 


L.  M.  T.  of  obsn.,  May  14,  1911  , 

I  7h  12.  4m  p.  m. 

Gr.  U.  C.  same  date          =10*  02.  lm  a.  m. 

Red.  to  long.  117°  W  W.=       -1. 3                     =  10     0. 8     a.  m. 

Hour  angle  of  Polaris,  west                                  =  9*  11.  Cm 


INSTRUMENTS  AND  METHODS. 
West  of  the  meridian,  a.  w.  obsn.,  U.  C.  in  p.  m. 


L.  M.  T.  of  obsn.,  Nov.  3,  1911 

Gr.  U.  C.,  Nov.  2  ^IG*  43.9m  p.  m. 

Red.  to  long.  117°  15'  W.  -1.3 

Hour  angle  of  Polaris,  west 


14-12 

|=  6h  31. 6m  a.  m. 

=10   42.6    p.  m. 


=  7h49.0m 
West  of  the  meridian,  a.  m.  obsn.,  U.  C.  in  a.  m. 


L.  M.  T.  of  obsn.,  Aug.  11,  1911  =  5h  05.9m  a.  m. 

Gr.  U.  C.,  same  date  — 4h  13. 6m  a.  m. 

Red.  to  long.  117°  15'  W.  ~1.3  =4   12.3    a.  m. 


Hour  angle  of  Polaris,  west 


Oh  53.6m 


East  of  the  meridian,  p.  m.  obsn.,  U.  C.  in  p.  m. 


Gr.  U.  C.,  Dec.  20,  1911 
Red.  to  long.  117°  15'  W. 

L.  M.  T.  of  U.  C.,  Dec.  20 
L.  M.  T.  of  obsn.,  same  date 

Hour  angle  of  Polaris,  east 


7h  34.8m  p.  m. 
-1.3 

7   33.5    p.  m. 
4  35.1    p.  m. 


60  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

East  of  the  meridian,  p.  m.  obsn.,  U.  C.  in  a.  TO. 


Gr.  U.  C.,  Sept.  2,  1911 
Ued.  to  long.  117°  15'  W. 

L.  M.  T.  of  U.  C.,  Sept.  2 
L.  M.  T.  of  obsn.,  Sept.  1 
Hour  angle  of  Polaris,  east 


=  2h  47.4m  a.  m. 
=      -1.3 


j=  2  46.1    a.  m. 
1+12 
=  6  34.0    p.  m. 


East  of  the  meridian,  a.  m.  obsn.,  U.  C.  in  p.  m. 


Gr.  U.  C.,  Mar.  19,  1911 
Red.  to  long.  117°  15'  W. 

L.  M.  T.  of  U.  C.,  Mar.  19 
L.  M.  T.  of  obsn.,  same  date 
Hour  angle  of  Polaris,  east 


Ih42.1mp.  m. 
-1.3 


|=  1  40.8    p.  in. 
1+12 
=  6  06.6    a.  m. 


~  7h34.2m 


INSTRUMENTS  AND  METHOD*:. 


61 


East  of  the  meridian,  a.  m.  obsn.,  U.  C.  in  a.  m. 


=  9*  46.4m  a.  m. 
=      -1.3 


=  9  45.1  a.  m. 
=  4  42.9  a.  m. 
=  5h02.2m 


Gr.  U.  C.,  May  18,  1911 
Red.  to  long.  117°  15'  W. 
L.  M.  T.  of  U.  C.,  May  18 
L.  M.  T.  of  obsn. 
Hour  angle  of  Polaris,  east 

67.  By  reference  to  the  preceding  diagram  showing  the  direction 
of  motion  of  Polaris  in  its  diurnal  circle,  Zenith 

the  motion  at  western  elongation  is  shown 
to  be  vertically  downward,  and  at  eastern 
elongation  the  motion  is  shown  to  be  ver- 
tically upward.  At  the  epoch  of  either 
western  or  eastern  elongation  the  motion 
of  Polaris  in  azimuth  is  zero. 

At  the  equator,  if  Polaris  could  be  ob- 
served; the  hour  angle  of  Polaris  at  elon- 
gation would  be  90°  0'  0"=6h  Om  0s 
sidereal  hour  angle^S11  59m  1.02"  mean 
time  hour  angle,  but  as  stations  of  ob- 
servation are  occupied  in  the  higher 
latitudes  the  hour  angle  of  Polaris  at 
elongation  decreases  progressively.  The 
reason  for  this  is  found  in  the  fact  that 
all  vertical  planes  intersect  at  the  ze- 
nith, and  the  point  of  tangency  of  a 
vertical  plane  with  the  diurnal  circle  of 
Polaris  occurs  at  points  corresponding 
to  decreasing  hour  angles  with  the  higher 
latitudes.  The  "spread"  of  the  two 
vertical  planes  intersecting  Polaris  at 
eastern  and  western  elongation  increases 
with  the  higher  latitudes,  giving  in-  celestial  sphere. 
creasing  azimuths  at  elongation  with  the  more  northern  latitudes. 


N 

Horizon 

FIG.  8.  — The  meridian  and 
vertical  planes  tangent  to 
the  diurnal  circle  of  Polaris 
as  viewed  from  inside  of  the 


62  :\f  ANUAL  OF  SURVEYING   INSTRUCTIONS. 

68.  Mean  time  hour  angle  of  Polaris  at  elongation:  £— the  sidereal 

hour  angle  in  angular  measure;  this  converted  into  time  measure, 

and  this  in  turn  converted  from  a  sidereal  time  interval  into  a  mean 

time  interval  gives  the  mean  time  hour  angle  of  Polaris  at  elongation: 

Cos  Z=cotan  5  tan  <£ 

Example  of  computing  the  mean  time  hour  angle  of  Polaris  at 
elongation,  April  3,  1915,  in  latitude  65°  0'  N.,  on  which  date  the 
declination  of  Polaris=88°  5V  20"  N.: 

^,=65°  0';  log  tan  <*>  =0. 331327 

6=88°  51'  20";      "     cotan  6  =8. 300530 


"    coat  =    8.631857 

Sidereal  hour  angle  =87°  32'  41" 


87°=5h    48m 
32'=         2m08' 
41"=  3- 

=5h    50mlls 
Reduction  to  mean  time  hour  angle  =      — Om  57* 


Mean  time  hour  angle  at  elongation  =5h  49m  14s 


ALTITUDE    OBSERVATION    OF  THE    SUN    TOR    APPARENT   TIME. 

69.  Altitude  observation  of  the  sun  for  apparent  time:  Z=hour 
angle  from  apparent  noon  in  angular  measure:  reverse  the  signs  of 
8  for  south  declinations: 


T       i  / 


/si 
V  co 


cos  1  (r+<M-5)  cos  i  (r-4>-5) 
70.  An  altitude  observation  of  the  sun  for  time  is  made  by  deter- 
mining the  correct  altitude  of  the  sun's  center  and  recording  the 
watch  time  at  the  epoch  of  observation.  The  following  order  of 
procedure  is  recommended  for  the  elimination  of  instrumental  errors, 
reduction  to  the  sun's  center,  and  practical  elimination  of  differen- 
tial refraction  : 


A.  M.   OBSERVATION. 


Thoroughly  level  the  transit. 

Observe  the  sun's  upper  limb,  recording  the  watch  time  of  observa- 
tion and  vertical  angle . 
Reverse  the  transit. 


INSTRUMENTS  AND  METHODS. 


63 


Observe  the  sun's  lower  limb,  recording  the  watch  time  of  observa- 
tion and  vertical  angle. 

The  mean  vertical  angle  is  equivalent  to  the  vertical  angle  to  the 
sun's  center  corresponding  to  the  mean  epoch  of  the  watch  readings. 

P.   M.  OBSERVATION. 

Thoroughly  level  the  transit. 

Observe  the  sun's  lower  limb,  recording  the  watch  time  of  observa- 
tion and  vertical  angle. 

Reverse  the  transit.  ) 

Observe  the  sun's  upper  limb,  recording  the  watch  time  of  observa- 
tion and  vertical  angle. 

The  mean  vertical  angle  is  equivalent  to  the  vertical  angle  to  the 
sun's  center  corresponding  to  the  mean  epoch  of  the  watch  readings. 

Example  of  altitude  observation  of  the  sun  for  apparent  time: 

Final  field  notes. 

August  24,  1909,  in  latitude  37°  16'  50"  N.,  and  longitude  102°  12' 
W.,  I  make  an  altitude  observation  upon  the  sun  for  time,  making 
two  observations,  one  each  with  the  telescope  in  direct  and  reversed 
positions,  observing  opposite  limbs  of  the  sun: 

Mean  observed  vertical  angle      =19°  39'  30" 
Mean  watch  time  of  observation  =  4h  56m  04s  p.  m. 
Watch  slow  of  local  mean  time   =         Om  561 

Field  record. 


Telescope. 

Sim's 
limbs. 

Watch  time. 

Vertical  angle. 

Direct  

J$L 

•    . 
4h55m22« 

19°  33'  00" 

Reversed..  . 

i 
TJr 

4  56  46 

19     46   00 

Mean  .  . 

4h,56m04B 

19°  39/30"=t> 

Refraction . 
Parallax. 


.-  -      2  40 
...=  4-      003 

h  —  19°  36'  58" 


64  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

True  vertical  angle=&=19°37' 
Zenith  distance  =f =70°23' 
Sun's  declination  =5=11°05/N. 

£=*  70°23/  r  f=70°23' 

0=  37  17  0=37  17 


<+ ) 

£  values= 
59°22/30//     22°05/30//     (r-0-H)=44°ll' 


(f-j-0)=107040'  (f-0) 

5=  11  05  (+)  5=11  05    (4-) 

5)=  96°35/     48017'30"     11°00/30//     (r-0-S) 


log  sin  i(r+0-5)=  9.  873054 

9.  575291 


cos  4(r+04- 5)=9. 707073  9. 448345 
cos  i(r-0-S)=9. 991934 


9.  699007  9.  699007 

========  73°=4h52: 

tan2  \t  «  9. 749338  41'  = 

tan  it  =  9.874669  24"= 


i=73°41/24//  t 

Apparent  time  of  observation     =4h54m46s  p.  m. 
Equation  of  time  -f-2  14 

Local  mean  time  of  observation =4h57m008  p.  m. 
Watch  time  of  observation          =4  56  04  p.  m. 

Watch  slow  of  local  mean  time  =      Om568 

MERIDIAN   OBSERVATION    OF  THE    SUN  FOR  APPARENT  NOON. 

71.  Meridian  observation  of  the  sun  for  apparent  noon. — With  the 
telescope  in  the  meridian  elevated  to  the  sun's  altitude,  the  watch 
times  of  transit  of  the  sun's  west  and  east  limbs  are  noted,  the  mean 
of  which  is  the  watch  time  of  apparent  noon;  if  the  observation  fails 
for  either  limb  the  reduction  to  the  sun's  center  is  accomplished  by 
adding  or  subtracting  68  seconds;  a  refinement  in  the  amount  of  thie 

time  is  hfl/1  hv  referrim*  to  the  "Rnhemeris  for  the  time  of  the  siin'p 


INSTRUMENTS  AND  METHODS.  65 

semi-diameter  passing  the  meridian  for  the  date  of  observation;  the 
setting  for  the  approximate  altitude  of  the  sun's  center  is: 


OBSERVING  PROGRAM. 

Determine  the  meridian  by  the  best  means  at  hand  and  compute 
the  altitude  setting  for  the  sun. 

Level  the  transit,  place  the  instrument  in  the  meridian,  and  ele- 
vate the  telescope  to  the  altitude  of  the  sun's  center. 

Note  the  watch  time  of  the  sun's  west  limb  tangent  to  the  vertical 
wire. 

Note  the  watch  time  of  the  sun's  east  limb  tangent  to  the  vertical 
wire. 

Take  the  mean  of  the  readings  for  the  watch  time  of  apparent 
noon  from  which  to  compute  the  watch  error  local  mean  time. 

Example  of  meridian  observation  of  the  sun  for  apparent  noon: 

Final  field  notes. 

August  14,  1909,  in  latitude  37°  16'  N.,  and  longitude  102°  16'  W., 
with  the  telescope  in  the  meridian  and  elevated  to  the  sun's  altitude, 
T  observe  the  sun's  transit  for  time,  noting  the  watch  time  of  transit 
of  each  limb: 

Mean  watch  time  of  apparent  noon=12h  00m  27* 
Watch  slow  of  local  mean  time        =         4m  06« 

Field  record. 
Setting:  90°  00' 

4,  ^  (~)37°  16'  N. 
3  ^  (-f)  14°  2^  N. 

v  ^         67°  09' 


€J-    Watch  time  of  transit,  W.  limb      =11^  59m  22« 
~£>  Watch  time  of  transit,  E-  limb      =12  01    32 

Watch  time  of  apparent  noon         =12h  00™  27* 
Apparent  noon    =12h  00m  00" 
Equation  of  time=    +  4     33 

Local  mean  time  of  apparent  noon=12  04    33 
Watch  slow  of  local  mean  time       =         4m  06« 

The  above  form  of  meridian  observation  of  the  sun  for  apparent 
noon  is  by  far  the  most  convenient  reliable  method  of  time  observation. 


()6  MANUAL,  OF  SUKVEYING   INSTRUCTIONS. 

TIME   FROM  THE   SOLAR  ATTACHMENT. 

72.  Several  of  the  approved  forms  of  solar  apparatus,  including 
principally  the  Smith  solar  attachment  and  the  Burt  solar  compass, 
have  a  graduated  arc  or  circle  mounted  normal  to  the  polar  axis  to 
indicate  the  apparent  time  of  observation.     The  reading  of  the  time 
arc  is  most  conveniently  checked  by  comparison  with  the  above 
form  of  meridian  observation  of  the  sun  for  apparent  noon.    An 
eiTor  in  the  reading  of  the  time  arc  or  hour  circle  may  be  corrected 
by  adjusting  the  circle,  or  allowed  for  as  an  index  error.     The  reading 
of  the  hour  circle  may  then  be  safely  accepted  as  giving  correct 
apparent  time  for  use  in  computing  or  taking  out  required  declina- 
tions of  the  sun  for  the  various  forms  of  solar  observations.     A  proper 
reading  of  the  hour  circle  may  be  safely  accepted  to  indicate  apparent 
time  at  which  moment  the  watch  reading  may  be  noted,  and  the 
watch  error  local  mean  time  determined  as  shown  in  the  preceding 
example  of  conversion  of  apparent  time  into  local  mean  time;  this 
result  derived  for  the  ivatch  error  local  mean  time  may  then  be  safely 
used  in  observations  on  Polaris  at  elongation,  but  for  observations 
upon  Polaris  by  the  hour  angle  method  the  time  should  be  determined 
by  one  of  the  more  refined  methods  already  given. 

LATITUDE. 

73.  It  is  absolutely  necessary  in  the  operation  of  any  solar  attach- 
ment to  employ  the  correct  latitude  of  the  station,  and  in  general  in 
altitude  observations  upon  the  sun  for  azimuth  or  time  the  latitude 
must  be  well  determined.     In  the  public-land  surveying  practice 
all  determinations  of  either  time  or  latitude  are  an  important  part 
of  the  program  of  operations  only  so  far  as  these  functions  finally 
enter  into  the  establishment  of  the  true  meridian;  all  classes  of 
observations  given  in  the  Manual  have  been  arranged  to  facilitate 
the  performance  of  solar  instruments,  and  for  this  purpose  a  definite 
knowledge  of  the  true  latitude  is  highly  important.     No  lack  of 
reasonable  precision  should  be  allowed  in  the  accepted  latitude. 
The  various  forms  of  observations  for  latitude  are  very  simple  and  a 
considerable  series  should  be  taken  in  every  group  of  surveys,  all 
reduced  to  the  township  boundaries  for  comparison,  until  a  satis- 
factory mean  has  been  obtained. 

MERIDIAN   ALTITUDE    OBSERVATION   OF  THE    SUN   FOR   LATITUDE. 

74.  Meridian  altitude  observation  of  the  sun  for  latitude. — Reverse 
the  sign  of  5  for  south  declinations: 

<*=90°  -f«  ~h 


INSTRUMENTS  AND  METHODS.  67 

The  following  observing  program  is  recommended: 
Thoroughly  level  the  transit  and  place  the  telescope  in  the  merid- 
ian elevated  to  the  sun's  approximate  altitude  at  noon. 

Observe  the  altitude  of  the  sun's  lower  limb  with  the  sun  slightly 
east  of  the  meridian. 
He  verse  the  transit. 

Observe  the  altitude  of  the  sun's  upper  limb  with  the  sun  slightly 
west  of  the  meridian. 

Take  the  mean  observed  vertical  angle  for  the  altitude  of  the 
sun's  center  at  apparent  noon. 

The  following  is  an  example  of  meridian  altitude  observation  of 
the  sun  for  latitude: 

Final  field  notes. 

October  5, 1909,  in  approximate  latitude  37°  2CK  N.,  and  longitude 
102°  04'  W.,  I  make  a  meridian  altitude  observation  of  the  sun  for 
latitude,  observing  the  altitude  of  the  sun's  lower  limb  with  the 
telescope  in  direct  posit  ion,  reversing  the  transit  and  observing  the 
sun's  upper  limb : 

Apparent  time  of  observation,  noon=12h  00m  00s 
Mean  observed  altitude  =47°  59'  45" 

Reduced  latitude  =37°  19'.3  N. 

Field  record. 
Setting:  90°  0(X 

<(>  ^  (-)37°20'N. 
5  ^  (-)    4°42/S. 

v  ^          47°  58' 
Lower  limb  47°  42' 

Upper  limb  48°  14' 

°f-  Observed  alt.,  lower  limb,  tel.  dir.=47°  43'  00" 

~b  Observed  alt.,  upper  limb,  tel.  rev.  =48°  W  30" 

Mean  observed  altitude,  v  =47°  59'  45" 

Refraction  -  0  52 

Parallax  -f  0  06 


/*=47°  58'  59" 
5=  4    41  42  S. 
d-A=37    19  19 


90°  00'  00" 


68 


MANUAL  OF  SURVEYING  I> >  Si  RUCTIONS. 


75.  The  above-described  observation  is  conveniently  combined 
with  the  meridian  observation  of  the  sun  for  time,  by  observing 
simultaneously  the  sun's  lower  and  west  limbs,  recording  the  watch 
time  and  the  vertical  angle  and  reversing  the  transit  in  the  interval 
of  about  2  minutes,  and  then  observing  simultaneously  the  sun?s 
upper  and  east  limbs.  The  settings  for  the  approximate  altitudes 
of  the  sun's  lower  and  upper  limbs,  respectively,  are: 


Example  of  meridian  observation  of  the  sun  for  time  and  latitude: 

Final  field  notes. 

June  8,  1910,  in  approximate  latitude  38°  54'  N.,  and  longitude 
77°  Olx.6  W.,  I  make  a  meridian  observation  of  the  sun  for  time  and 
latitude,  observing  simultaneously  the  altitude  of  the  sun's  lower 
limb  and  the  transit  of  the  sun's  west  limb,  reversing  the  telescope 
and  observing  simultaneously  the  altitude  of  the  sun's  upper  limb 
and  the  transit  of  the  sun's  east  limb: 

Mean  observed  altitude  =73°  55'  30" 

Reduced  latitude  =38°  53'.7  N. 

Mean  watch  time  of  observation  =12h  OGm  40" 
Watch  fast  of  local  mean  time     =         7m  58* 

Field  record. 

Setting:  90°  (XX    #g 

4>^      (-)38°54'N. 

5=      (-f).22°49'N. 


Lower  limb 
Upper  limb 


73°  5$' 
73°  39' 
74°  11'. 


Position  of  telescope. 

Position  of  sun. 

Watch  time 
transit. 

Observed  ver- 
tical angle. 

Direct  

n 

12h    OS*    37* 

73°    42'    30" 

Reversed  

"b 

12      07      42 

74      08     30 

Mean... 

12h    06m    40« 

73°    55'    30" 

Refrac^'on. 
Parallax. 


-16 
H-02 


h : =  73°    55'    16" 

5=» 22°  4y  00";  90° +5 „ ..,..;..., =112     49     00 


0=38053'.7N.«90°-fS-fc =*  38°    53'    44" 


INSTRUMENTS  AND  METHODS.  69 

Watch  time  of  apparent  noon = 12h    06m    40* 

Apparent  noon = 12h    00m    00s 

Equation  oi  time . .  =       —  1       18 

Local  mean  time  of  apparent  noon. =11      58       42 


Watch  fast  of  local  mean  time =  7m    58s 

The  known  latitude  of  the  above  station  is  38°  53'  40",-  but  it  can 
not  be  assumed  that  any  one  altitude  observation  of  the  sun  will 
always  give  a  result  so  close  to  the  true  latitude.  In  general  a  better 
determination  of  the  latitude  by  this  method  is  possible  only  by 
making  a  series  of  observations  on  successive  days,  or  by  combining 
the  result  with  Polaris  observations  for  latitude. 

For  the  purpose  of  a  test  as  to  the  accuracy  of  the  above  time 
observation,  the  same  watch  was  compared  with  a  Western  Union 
telegraph  clock  as  follows: 

75th  meridian  time  of  comparison.— 12h    00m    00» 
Correction  for  longitude  77°  1.6'.. .  =      -08       06 

Local  mean  time  of  comparison.  .  .=llh    51m    54* 
Watch  time  of  comparison =11      59       56 


Watch  fast  of  local  mean  time  .....  =  8m    02* 

ALTITUDE    OBSERVATION    OF   POLARIS   FOR   LATITUDE. 

76.  Altitude  observation  of  Polaris  at  upper  culmination  for  latitude: 


Altitude  observation  of  Polaris  at  lower  culmination  for  latitude: 
The  mean  time  hour  angle  of  Polaris  at  lower  culmination  is  11 
hours  58  minutes  2  seconds: 


The  settings  for  the  approximate  altitude  of  Polaris  at  upper  and 
lower  culminations,  respectively,  are: 


The  following  program  is  recommended  in  altitude  observations 
of  Polaris  at  culmination  for  latitude. 

Compute  the  local  mean  time  and  watch  time  of  culmination. 

Thoroughly  level  the  transit. 

About  four  minutes  before  culmination  observe  the  altitude  of 
Polaris  with  the  telescope  in  direct  position. 


70  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

Reverse  the  transit  and  observe  the  altitude  of  Polaris. 

Again  level  the  transit. 

Observe  the  altitude  of  Polaris  with  the  telescope  in  the  reversed 
position. 

Reverse  the  transit  to  the  direct  position  of  the  telescope  and  again 
observe  the  altitude  of  Polaris. 

Take  the  mean  observed  altitude  to  use  in  the  reduction. 

Example  of  altitude  observation  of  Polaris  at  lower  culmination 
for  latitude: 

Final  field  notes. 

June  19,  1910,  in  approximate  latitude  38°  54'  N.,  and  longitude 
77°  01'. 6  W.,  I  make  an  altitude  observation  on  Polaris  at  lower 
culmination  for  latitude,  making  four  observations,  two  each  with 
the  telescope  in  direct  and  reversed  positions: 
Watch   fast   of   75th   meridian 

standard  time  by  comparison  =  Om  24s 

Mean  watch  time  of  observation    =  7b  44m  37s  p.  m. 

Mean  observed  vertical  angle       =  37°  44'  00" 

Reduced  latitude  38°  53'. 4  N. 

Field  record. 

Setting:  90°  00' 

6^88°  49/ 


90°-$^  1°  11' 
54' 


Gr.  U.  C.  of  Polaris,  June  19,  1910  =     7h  39.7m     a.  m. 

Reduction  to  longitude  77°  1.6'  W.  =        -0.8 

Reduction  to  lower  culmination  =4-11  58.0 


7h36.9m     p.  in. 


L.  M.  T.  of  L.  C.  of  Polaris,  June  19  =      7h  36m  54-  p.  m. 

Watch  fast  of  75th  meridian  standard  time  by 
comparison  with  a  Western  Union  telegraph 
clock  —f  0  24 

Correction  for  longitude  77°  Olx.6  W.  =-f       8    06 

Computed  watch  time  of  lower  culmination        ==     7h  45m 24"  p.m. 


INSTRUMENTS  AND  METHODS. 


71 


. 

Telescope. 

Watch 
time. 

Vertical 
angle. 

Direct    

7h   4Qm  HB 

37°  42'  20" 

Reversed                                                                     .  

7    42     45 

37    44   30 

Reversed 

7    46     39 

37    45   30 

Direct  .  .                       .                         

7    48     50 

37    43   30 

MeftTi                            .  .      .      .         

7h  4401  378 

37°  44'  00" 

Refraction.  .  . 

-1    15 

S«88°  49'  20";  900-/; 


ft=370  42'  45" 
=  1     10   40 


38°  53'  25" 


AZIMUTH. 

THE    SOLAR    ATTACHMENT. 

77.  The  solar  attachment  to  the  engineer's  transit  has  been 
designed  f or  instrumentally  setting  off  the  sides  of  the  "  pole-zenith- 
sun"  triangle  in  agreement  with  their  angular  values  at  the  station 
and  time  of  observation.  The  sun's  image  may  be  brought  into  the 
line  of  collimation  of  an  auxiliary  telescope  by  orientation  of  the 
transit  to  the  position  where  the  instrumental  parts  are  made  parallel 
to  the  respective  sides  of  the  celestial  triangle,  whereupon  the  verti- 
cal plane  of  the  "  pole-zenith "  arc  of  the  solar  attachment  will 
coincide  with  the  true  meridian.  Skillfully  handled,  the  solar  at- 
tachment will  give  at  once  close  approximations  to  the  true  meridian 
comparing  favorably  for  accuracy  with  direct  observations.  The 
advantage  in  the  proper  use  of  the  solar  attachment  is  found  in  its 
rapid  and  close  determinations  of  the  meridian  in  heavy  timber, 
dense  undergrowth,  and  strong  wind,  in  low  swamp  or  on  high 
mountain  ascents,  and  under  nearly  all  other  difficult  physical 
situations  encountered  in  the  field,  avoiding  in  its  proper  use  accumu- 
lative errors  incident  to  the  prolongation  and  deflection  of  transit 
lines,  and  deviations  in  the  azimuth  of  latitudinal  lines.  Several 
ingenious  instruments  have  been  devised  for  this  purpose,  but  the 
Smith  solar  attachment,  invented  by  Benjamin  II.  Smith,  of  Colo- 
rado, in  1880,  has  given  the  most  general  satisfaction  of  any  solar 
instrument  in  meeting  the  special  requirements  of  the  surveying 
service  of  the  General  Land  Office  wherein  it  has  been  developed 
to  a  state  of  efficiency  which  has  fully  warranted  the  adoption  of 
this  model  as  a  standard  instrument  for  use  in  the  public-land 
surveys. 


72  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

Owing  to  the  different  details  in  the  design  of  the  J3mith  solar 
attachment  as  constructed  by  various  instrument  makers  it  is 
impossible  to  discuss  fully  the  test  and  adjustment  of  each  without 
giving  a  complete  description  of  the  several  models,  and  this  would 
lead  away  from  the  purpose  of  the  Manual.  The  standard  model, 
embracing  the  most  recent  improvements,  is  therefore  selected  for 
description,  and  discussion  of  the  theory,  adjustment  and  use  of  the 
Smith  solar  attachment.  The  supervising  officers  will  furnish  the 
surveyors  with  suitable  instructions  relative  to  the  test  and  adjust- 
ment of  any  other  special  instruments  supplied  to  them,  published 
in  circular  form  as  deemed  expedient. 

DESCRIPTION. 

78.  The  working  parts  of  the  Smith  solar  attachment  consist  of 
five  fundamental  features,  each  performing  its  own  distinctive 
function.  The  principles  involved  have  been  adapted  to  various 
types  of  construction,  and  the  efficiency  of  the  different  designs  is 
related  directly  to  the  perfection  which  may  be  attained  in  making 
a  proper  adjustment  in  the  field,  the  stability  of  the  adjustments 
when  made,  and  the  compactness  of  the  design,  considering  protect 
tion  to  the  working  parts  and  proper  distribution  of  weight.  The 
five  fundamental  working  parts  consist  of: 

1.  An  auxiliary  telescope  whose  line  of  collirnation  is  the  polar 
axis  of  the  solar  attachment;  the  telescope  may  be  revolved  in  col- 
lar bearings  which  are  securely  mounted  on  a  vertical  limb. 

2.  The  vertical  limb  is  mounted  on  a  horizontal  axis  and  has  a 
graduated  latitude  arc  in  its  vertical  plane. 

3.  A  plane  mirror  at  the  objective  end  of  the  auxiliary  telescope 
with  an  axis  normal  to  the  line  of  collimation,  and  an  arm  leading 
to  a  graduated  declination  arc. 

4.  An  hour  circle  on  the  auxiliary  telescope  mounted  normal  to 
the  line  of  collimation. 

5.  A  set  of  equatorial  wires  parallel  to  the  axis  of  the  reflector. 
In  all  the  forms  of  construction  of  the  Smith  solar  attachment  the 

auxiliary  telescope  is  mounted  in  a  vertical  plane  parallel  to  the 
transit  telescope.  Thus,  if  the  instrument  is  in  proper  adjustment 
and  oriented  to  the  true  meridian,  the  polar  axis  of  the  solar  attach-^ 
ment  may  be  made  parallel  to  the  earth's  polar  axis  by.  setting  off 
the  true  latitude  of  the  station.  The  sun's  rays  are  brought  into  the 
auxiliary  telescope  by  means  of  the  mirror,  due  allowance  being 


INSTRUMENTS  AND  METHODS. 


73 


FIG.  9.— The  solar  transit  as  it  appears  in  use. 
55465°— 19 6 


74  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

made  for  the  sun's  declination  north  or  south  of  the  equator,  but  to 
bring  the  sun's  image  into  the  auxiliary  telescope  the  latter  must  be 
revolved  in  its  collar  bearings  until  the  reading  of  the  hour  circle 
agrees  with  the  sun's  apparent  time.  When  the  auxiliary  telescope 
is  thus  revolved  the  sun's  image  will  traverse  the  field  of  the  eye- 
piece parallel  to  the  equatorial  wires  with  the  limbs  of  the  disk  tan- 
gent to  the  same.  If  the  transit  is  turned  in  azimuth  the  sun's  image 
will  immediately  depart  from  the  equatorial  wires,  except  at  noon 
when  the  image  will  follow  the  equatorial  wires  whether  the  transit 
be  turned  slightly  in  azimuth  or  the  auxiliary  telescope  be  revolved 
in  hour  angle.  At  apparent  noon  the  declination  arc  is  in  a  ver- 
tical plane  and  at  this  time  an  absolute  determination  may  be  made 
of  the  correctness  of  the  reading  of  this  arc. 

In  the  modern  construction  the  solar  attachment  is  mounted 
upon  the  east  standard  of  a  regular  light  mountain  model  full  engi- 
neer's transit,  the  horizontal  circle  of  which  has  a  diameter  of  4J 
inches,  with  a  vertical  circle  of  4  inches  diameter.  The  horizontal 
distance  between  the  vertical  planes  of  the  transit  and  auxiliary  tele- 
scopes is  a  trifle  less  than  4  inches.  The  auxiliary  telescope  has  a 
focal  length  of  4|  inches  and  a  magnifying  power  of  about  10  diam- 
eters. The  latitude  arc  has  a  radius  of  3  inches,  and  the  declination 
arc  has  a  radius  of  3J  inches.  Upon  the  latter  arc  the  graduations 
read  the  true  declination  and,  as  the  mirror  needs  to  be  turned  only 
5°  to  correspond  to  a  change  of  10°  in  the  sun's  declination,  the  gradu- 
ations are  made  in  one-half  space,  i.  e.,  an  interval  of  10°  on  the  arc 
as  graduated  occupies  a  segment  of  only  5°.  At  zero  declination 
the  plane  of  the  mirror  is  at  45°  to  the  line  of  sight  of  the  auxiliary 
telescope.  Both  telescopes  are  fitted  with  the  necessary  colored 
glass  shades  for  observing  the  sun.  The  base  plate  of  the  solar  is 
mounted  upon  three  foot  posts,  adjustable  by  means  of  opposing 
capstan  nuts.  This  three-point  base  forms  a  right-angled  triangle, 
with  one  side  horizontal  and  one  side  vertical,  thereby  permitting 
adjustment  in  either  of  two  directions:  (a)  One  about  a  horizontal 
axis,  and  (b)  one  about  a  vertical  axis.  Suitable  capstan  nuts  are 
also  placed  at  one  end  of  the  auxiliary  telescope  to  provide  for  its 
proper  adjustment  with  respect  to  the  axis  of  the  latitude  arc. 

Good  solar  work  must  depend  first  of  all  upon  the  proper  adjust- 
ment of  the  transit  upon  which  it  is  mounted,  with  great  care  in  keep- 
ing every  working  part  cleaned,  suitably  oiled  to  work  smoothly,  and 


INSTRUMENTS  AND  METHODS.  75 

protected  from  adverse  weather  and  injury.  The  same  precautions 
are  due  the  solar  attachment.  It  will  give  very  efficient  meridional 
performance  if  properly  adjusted  and  operated;  nothing  less  can  be 
conceded. 

Before  starting  in  with  the  adjustments  it  should  be  determined 
that  the  auxiliary  telescope  revolves  smoothly  in  its  collar  bearings, 
neither  too  tight  nor  too  loose ;  that  there  is  free  and  smooth  motion 
to  the  latitude  and  declination  arcs;  that  the  clamps  are  positive  and 
the  tangent  motions  smooth  and  free  in  either  direction;  that  the 
eye-piece  is  carefully  focused  upon  the  cross  wires;  and  that  the 
objective  is  carefully  focused  upon  any  quite  distant  object,  then 
secured  in  this  position.  The  eye-piece  turns  freely  and  has  a  pin- 
which  travels  in  a  guide  slot;  this  pin  is  not  a  clamp.  The  objective 
may  be  moved  by  first  loosening,  then  pushing  the  screw,  which  will 
be  found  to  travel  in  a  guide  slot  near  the  lower  (or  left  hand)  collar 
bearing. 

ADJUSTMENT. 

79.  The  field  adjustments  of  the  solar  attachment  should  be  con- 
sidered in  the  following  order: 

1.  The  equatorial  wires  must  be  made  parallel  to  the  axis  of  the 
reflector. 

2.  The  line  of  sight  of  the  auxiliary  telescope  must  lie  in  its  true 
turning  axis. 

3.  The  polar  axis,  or  line  of  sight  of  the  auxiliary  telescope,  must 
be  normal  to  the  axis  of  the  latitude  arc,  describe  a  true  vertical 
plane  when  turning  on  said  axis,  and  said  vertical  plane  must  be 
parallel  to  the  vertical  plane  of  the  transit  telescope. 

4.  The  latitude  arc  should  read  zero  when  the  auxiliary  telescope 
is  horizontal. 

5.  The  declination  arc  should  at  all  times  read  the  true  declina- 
tion of  the  sun  plus  the  refraction  in  polar  distance. 

6.  The  hour  circle  should  read  the  sun's  apparent  time. 

There  are  two  or  more  methods  of  testing  each  and  every  adjust- 
ment, but  those  stated  below  are  without  doubt  the  simplest,  and 
most  rapid  and  reliable  of  all  field  methods.  The  true  meridian 
should  be  established  by  Polaris  or  other  independent  observation, 
upon  which  to  test  the  solar,  but  otherwise  it  plays  only  a  small  part 
in  the  adjustments  of  the  solar  attachment.  The  true  latitude  of  the 
station  must  be  definitely  known.  There  should  be  a  clear  view  to  a 


76  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

distant  object  in  the  horizon,  but  if  an  object  less  than  a  mile  away 
must  be  utilized  due  allowance  may  be  made  for  the  horizontal  dis- 
tance between  the  vertical  planes  of  the  transit  and  auxiliary  tele- 
scopes. 

1.  The  equatorial  wires. — Set  up  the  instrument  as  in  a  regular 
solar  observation,  setting  off  the  known  latitude,  declination  and 
apparent  time,  and  bring  the  sun's  image  accurately  between  the 
equatorial  wires  by  orienting  the  transit  approximately  to  the  meri- 
dian, in  which  position  the  instrument  should  be  clamped.     (See 
fig.  9.)     Turn  the  auxiliary  telescope  in  hour  angle,  causing  the  sun's 
image  to  travel  across  the  field  from  side  to  side.     If  the  image  follows 
the  equatorial  wires  accurately  the  latter  are  parallel  to  the  axis  of 
the  reflector  as  required.     If  the  sun's  image  departs  materially  from 
the  equatorial  wires,  the  capstan  screws  which  hold  the  diaphragm 
should  be  loosened  and  the  reticle  may  be  rotated  until  the  equa- 
torial wires  are  made  to  agree  with  the  path  of  the  sun's  image  across 
the  field,  then  return  each  capstan  screw  to  a  proper  seat. 

2.  Collimation  of  the  auxiliary  telescope. — Swing  the  mirror  to  give 
a  direct  view  through  the  auxiliary  telescope.     (See  fig.  10.)     Set 
the  line  of  sight  on  a  distant  point  and  clamp  the  instrument. 
Revolve  the  auxiliary  telescope  12  hours  in  hour  angle.  If  the  line 
of  sight  remains  fixed  on  the  distant  point  it  agrees  with  the  turning 
axis  as  required.     If  after  revolution,  the  line  of  sight  appears  to  be 
above  or  below,  or  to  the  right  or  left,  of  the  distant  point,  one-half 
of  the  differences  should  be  taken  up  with  the  capstan  screws  which 
control  the  diaphragm.     The  test  should  be  repeated  until  the  auxili- 
ary telescope  is  in  perfect  collimation. 

3.  The  polar  axis. — Carefully  level  the  transit  and  then  sight  the 
main  telescope  to  the  distant  point  and  clamp  the  instrument;  sight 
toward  the  same  point  with  the  auxiliary  telescope,  and  place  the 
striding  level  on  the  latitude  axis.     (See  fig.  10.)    The  striding  level 
should  be  reversed  to  see  if  there  is  any  error  in  the  level  itself,  and 
if  so  take  the  mean  position  for  the  true  indication  of  the  level.    If 
the  latitude  axis  is  not  horizontal  it  may  be  made  so  by  adjusting  the 
lower  pair  of  capstan  nuts  on  the  base  frame  of  the  solar  attachment. 
If  the  line  of  sight  of  the  auxiliary  telescope  is  not  parallel  to  that 
oi;  the  main  telescope  it  may  be  made  parallel  by  means  of  the  left- 
hand  upper  pair  of  capstan  nuts  on  the  base  frame  of  the  solar.    After 
fulfilling  the  foregoing  conditions  turn  the  transit  180°  in  azimuth  and 
reverse  both  telescopes  so  as  to  sight  again  to  the  same  distant  object, 


INSTRUMENTS  AND  METHODS. 


77, 


FIG.  10.— Direct  sighting  through  the  auxiliary  telescope,  with  the  mirror  swung  to 
a  central  position,  and  showing  the  striding  level  on  the  latitude  axis. 


78  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

setting  the  main  telescope  upon  the  object.  (See  fig.  11.)  If  the 
auxiliary  telescope  does  not  again  sight  upon  the  distant  object,  one- 
half  the  error  is  due  to  its  line  of  sight  not  being  at  right  angles  to  the 
axis  of  the  latitude  arc.  Take  up  half  of  the  amount  of  the  error 
by  means  of  the  pair  of  capstan  nuts  at  one  end  of  the  auxiliary 
telescope,  and  take  up  half  of  the  error  by  again  correcting  the 
left-hand  upper  pair  of  capstan  nuts  on  the  base  frame  of  the  solar. 
The  line  of  sight  of  the  auxiliary  telescope  should  now  be  normal 
to  the  axis  of  the  latitude  arc,  should  describe  a  vertical  plane  when 
turning  on  said  axis,  and  said  vertical  plane  should  be  parallel  to  the 
vertical  plane  of  the  transit  telescope.  The  tests  should  be  carefully 
repeated  until  the  adjustments  are  perfected. 

4.  The  latitude  vernier. — Carefully  level  the  transit,  clamp  the 
latitude  arc  at  zero,  and  place  the  striding  level  in  position  on 
the  auxiliary  telescope.     (See  fig.  12.)    The  striding  level  should  be 
reversed  to  see  if  there  is  any  error  in  the  level  itself,  and  if  so  take 
the  mean  position  for  the  true  indication  of  the  level.     If  the  aux- 
iliary telescope  is  not  horizontal  it  may  be  made  so  by  means  of  the 
tangent  motion  of  the  latitude  arc.     When  the  auxiliary  telescope 
has  been  made  truly  horizontal  the  reading  will  indicate  the  index 
error  of  the  vernier  of  the  latitude  arc.  The  vernier  is  held  in  posi- 
tion by  two  screws  passing  through  elongated  holes,  and  by  loosening 
the  screws  the  vernier  may  be  shifted  to  read  zero,  or  the  difference 
from  zero  may  be  carried  as  an  index  error. 

5.  The  declination  vernier. — A  few  minutes  before  apparent  noon 
set  the  instrument  in  the  established  meridian.     Set  off  the  known 
true  latitude,  allowing  for  any  index  error  in  the  vernier  of  the  lati- 
tude arc.    Carefully  level  the  transit  and  clamp  the  instrument 
with  the  main  telescope  in  the  meridian.     Bring  the  sun's  image 
into  the  field  of  the  auxiliary  telescope  by  turning  this  telescope  in 
hour  angle.    At  apparent  noon  bring  the  sun's  image  accurately 
between  the  equatorial  wires  by  means  of  the  tangent  motion  of  the 
declination  arc.    The  difference  between  the  reading  of  the  declina- 
tion arc  and  the  calculated  declination  (corrected  for  refraction) 
will  indicate  the  index  error  of  the  vernier  of  the  declination  arc. 
This  vernier  is  also  held  in  position  by  two  screws  passing  through 
elongated  holes,  and  by  loosening  the  screws  the  vernier  may  be 
shifted  to  read  the  calculated  declination  for  apparent  noon  of  that 
date,  or  the  difference  may  be  carried  as  an  index  error.     This  test 
should  be  made  every  day  the  instrument  is  used.     If  by  some 


INSTRUMENTS  AND  METHODS. 


FIG.  11.— The  auxiliary  telescope  in  reversed  position. 


80  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

failure  in  the  adjustments  of  the  solar  attachment  a  difference  of  as 
much  as  30"  from  previous  tests  should  be  discovered  in  the  noon 
observation,  the  new  error  will  generally  be  found  in  one  of  three 
places:  (a)  The  auxiliary  telescope  may  be  out  of  collimation;  (6)  the 
vernier  of  the  latitude  arc  may  have  become  loose  and  shifted;  or  (c) 
the  vernier  of  the  declination  arc  may  have  become  loose  and  shifted. 
Any  slight  error  in  the  other  adjustments,  or  in  the  determination  of 
the  established  meridian,  will  not  appear  in  the  noon  test  of  the 
declination  arc. 

6.  The  hour  circle. — A  few  minutes  before  apparent  noon  set  the 
instrument  in  the  established  meridian .  Level  the  transit  and  clamp 
the  instrument  with  the  main  telescope  in  the  meridian  and  elevated 
to  the  sun's  altitude.  Set  your  watch  to  read  12  o'clock  as  the 
sun's  center  crosses  the  vertical  wire  of  the  main  telescope.  At  any 
convenient  time  thereafter  set  off  the  proper  readings  on  the  latitude 
and  declination  arcs,  and  with  the  instrument  in  the  meridian,  bring 
the  sun's  image  to  the  center  of  the  field  of  the  auxiliary  telescope 
and  observe  the  watch  time.  If  the  reading  of  the  hour  circle  agrees 
with  the  watch  it  is  in  adjustment;  if  not,  it  may  be  made  to  read 
apparent  time  by  loosening  the  set  screw  which  holds  the  hour  circle 
in  position  and  shifting  the  circle  until  the  reading  agrees  with  the 
watch,  care  being  taken  not  to  move  the  auxiliary  telescope  in  hour 
angle  until  after  the  set  screw  is  again  seated.  The  test  may  then 
be  repeated  as  often  as  desirable. 

USE. 

80.  Before  using  the  solar  attachment  the  latitude  of  the  station 
and  the  sun's  declination  (properly  corrected  for  refraction  in  polar 
distance)  must  be  l:nown  and  accurately  set  off  on  the  respective 
arcs.  The  instrument  is  carefully  leveled  and  the  apparent  time 
set  off  on  the  hour  circle.  The  transit  is  then  oriented  to  the  meri- 
dian. The  plates  are  generally  first  set  at  zero  and  the  sun's  image 
brought  into  the  field  of  the  solar  telescope  before  setting  the  lower 
clamp;  thereupon  the  sun's  image  is  brought  accurately  between 
the  equatorial  wires  with  the  lower  tangent  motion;  this  gives  the 
solar  meridian.  The  transit  may  then  be  used  for  any  normal  func- 
tion. The  solar  meridian  may  be  tested  as  many  times  as  may  be 
desirable  by  simply  setting  the  plates  back  to  zero  and  turning  the 
auxiliary  telescope  in  hour  angle  to  the  apparent  time;  this  brings 
the  sun's  image  again  to  the  center  of  the  field.  The  sun's  declina- 
tion is  constantly  changing  at  a  very  slow  rate,  so  that  it  is  necessary 


INSTRUMENTS  AND  METHODS. 


81 


FIG.  12.— The  striding  level  on  the  auxiliary  telescope. 


82  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

to  correct  the  reading  on  the  declination  arc  with  its  tangent  motion 
to  agree  with  the  declination  of  the  sun  for  the  apparent  time  of 
observation. 

The  great  advantage  of  the  Smith  solar  over  all  other  forms  of 
solar  attachment  is  found  in  the  fact  that  the  latitude  and  declina- 
tion arcs  remain  clamped  while  the  transit  is  being  used  in  any  nor- 
mal function.  Upon  setting  up  at  a  second  station  it  is  necessary 
merely  to  correct  the  latitude  and  declination  arcs  with  their  tangent 
motions  to  agree  with  any  change  from  the  previous  station.  For 
this  reason  it  may  be  operated  more  rapidly  than  any  other  form 
of  solar  attachment.  In  fact,  the  solar  meridian  is  so  quickly  deter- 
mined that  the  observation  is  usually  repeated  at  every  station. 

The  same  restrictions  which  must  be  recognized  in  making  direct 
observations  on  the  sun  operate  in  the  same  way  as  a  prohibition  in 
the  use  of  any  solar  instrument.  There  are  only  two  such  limita- 
tions: (1)  When  the  sun  is  within  two  hours,  or  possibly  an  hour  and 
one-half  of  the  meridian;  and  (2)  when  the  sun  is  low  in  the  horizon. 
In  the  first  instance,  the  sun's  relative  rate  of  change  in  azimuth  is 
much  greater  than  the  rate  of  change  in  altitude,  and  a  small  error 
in  adjustment  or  in  setting  the  arcs  is  greatly  multiplied.  In  the 
second  case  the  refractions  are  great,  more  or  less  uncertain,  and 
changing  rapidly. 

The  latitude  of  the  station  should  always  be  determined  with 
great  care.  Altogether  too  many  maps  are  unreliable  in  this  respect. 
If  the  latitude  has  been  determined  by  competent  observers,  well 
and  good,  it  may  be  free  from  error,  but  the  direct  altitude  observa- 
tion upon  the  sun  for  latitude  is  so  simple  and  the  reduction  so  easy 
that  every  operator  of  a  solar  transit  should  make  it  a  practice  to 
accomplish  direct  observations  on  the  sun  for  latitude  on  as  many 
successive  days  as  may  be  necessary  to  give  a  reliable  determination 
of  the  true  latitude  of  any  unknown  station. 

TEST. 

81.  When  the  solar  attachment  has  been  put  in  good  adjustment 
it  is  proper  to  test  it  frequently  on  a  true  meridian  established  by 
Polaris  observation  or  other  approved  method.  The  test  consists 
merely  in  determining  a  meridian  with  the  solar  and  comparing 
this  indication  with  the  true  meridian  established  by  other  reliable 
method.  The  test  should  be  repeated  in  a.  m.  and  p.  m.  hours  at 


INSTRUMENTS  AND  METHODS. 


83 


frequent  intervals,  and  the  noon  observation  should  most  certainly 
be  taken  every  day  that  the  solar  is  used . 

The  selection  of  the  method  of  observation  to  establish  the  true 
meridian  will  be  made  by  the  surveyor,  the  facts  relative  to  which 
are  to  appear  in  the  final  field  notes,  and  the  solar  attachment  may 
be  considered  in  satisfactory  adjustment  when  all  meridional  tests 
during  the  usual  hours  of  solar  work  are  found  to  come  within  V  30" 
of  the  true  meridian,  whereupon  the  certificate  of  the  surveyor's 
examination  of  the  adjustments  of  his  instrument  will  take  the 
following  form: 


Field  record. 


Final  field  notes. 


Buff  Solar  Transit  No.  8028. 
Sun's  declination  at  Greenwich  noon 
=5h58ma.  m.,  localapp.t.   =18°  32'  04"  S. 
Dtff.  IQh,  —382"  =         6  22    S. 


3h,58ra  p.m. 


=  18°  38' 26"  S. 


/8°S. 


6 
7 
8 
9 

10 
II 
Noon 
1 
2 
3 
4 

/ 

/ 

/ 

N 

0*0. 

,/ 
/30 

r* 

/ 

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P.M.  5 

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*  Adjust  auxiliary  telescope  forcollimation, 


Nov.  16,  1911,  at  my  station  in  Sec. 
35,  T.  11  N.,  R.  6  E.,  5th  Prin.  Mer., 
Arkansas,  in  latitude  35°  32.9'  N.,  as 
determined  by  the  mean  of  altitude 
observations  on  the  sun  on  Sept.  26 
and  29,  1911,  heretofore  described,  and 
longitude  90°  25'  W.,I  examine  the  ad- 
justments of  the  instrument  and  cor- 
rect all  errors.  I  then  test  the  solar 
apparatus  by  comparing  its  indications 
hourly  with  the  true  meridian  estab- 
lished by  Polaris  observation  Sept.  26, 
1911,  heretofore  described. 

At9h20«>a.  m.,app.t.,  I  set  off  35°33'N., 
on  the  lat.arc;  18° 32'. 5 S.,  onthedecl. 
arc;  and  determine  a  meridian  with  the 
solar  which  I  find  to  agree  with  the 
true  meridian. 

At  app.  noon,  with  the  lat.  arc  un- 
changed, I  observe  the  sun  on  the 
meridian;  the  resulting  reading  of  the 
decl.  arc  is  18°  34 '.5  S.,  which  agrees 
with  the  computed  decimation  of  the 
sun. 

At  3hOm  p.  m..  app.t.,  with  the  lat.  arc 
unchanged,  I  set  off  18°  36'  S. ,  on  the 
decl.  arc;  and  determine  a  meridian 
with  the  solar  which  I  find  to  agree 
with  the  true  meridian. 

As  all  of  the  solar  observations  during 
the  usual  hours  of  solar  work  come 
within  1'  30"  of  the  true  meridian,  I 
conclude  that  the  adjustments  of  the 
instrument  are  satisfactory. 


THE    SOLAR    COMPASS. 


82.  The  Burt  solar  compass,  invented  by  William  A.  Burt,  of 
Michigan,  in  1836,  was  the  first  solar  instrument,  and  since  its  intro- 


84  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

duction  the  instrument  has  been  extensively  used  in  public-land 
surveying;  the  solar  compass  has  given  general  satisfaction  and  is 
still  used  to  some  extent  in  the  public-land  surveys,  but  in  recent 
years  it  has  been  largely  superseded  by  the  more  complete  instru- 
ment already  described.  The  Burt  solar  apparatus  is  designed  for 
mounting  upon  an  open-sight  compass,  commonly  used  in  the 
early  public-land  surveys.  A  polar  axis  is  fitted  in  line  with  the 
terrestrial  sights  when  the  plate  verniers  are  set  at  zero.  The  in- 
clination of  the  polar  axis  is  controlled  by  a  latitude  arc  mounted  in 
the  same  vertical  plane.  Normal  to  the  polar  axis  there  is  a  revolv- 
ing arm  upon  which  is  mounted  a  declination  arc  and  two  solar  lines 
of  collimation,  one  for  north  declination  of  the  sun,  and  one  for  south 
declination.  Each  line  of  collimation  consists  of  a  lens  and  silver 
plate  or  disk  mounted  upon  opposite  ends  of  the  revolving  arm; 
parallel  equatorial  lines  are  drawn  upon  each  disk  symmetrical  with 
the  axis  of  the  opposite  lens.  Two  adjustments  are  peculiar  to  the 
Burt  solar  compass,  which  are  here  given  for  the  surveyor's  reference 
in  the  field;  these  adjustments  should  be  made  when  the  sun  is  within 
an  hour  of  the  meridian. 

(1)  To  make  the  solar  lines  of  collimation  parallel. — The  declination 
arm  will  be  detached  and  replaced  by  an  auxiliary  frame  upon  which 
the  arm  will  be  laid.     Set  the  latitude  and  declination  arcs  approx- 
imately correct  for  the  hour,  date  and  station,  and  bring  the  sun's 
image  upon  either  disk  as  in  an  orientation  to  the  meridian.     Now 
turn  the  arm  over,  without  reversing  from  end  to  end,  and  see  if  the 
sun's  image  again  comes  between  the  equatorial  lines;  if  not,  adjust 
the  disk  for  half  the  difference  and  repeat  the  test  until  satisfactory. 
When  this  has  been  accomplished,  reverse  the  arm  from  end  to  end 
for  the  purpose  of  adjusting  the  second  disk  with  respect  to  the 
opposite  lens.     Remove  the  auxiliary  frame  and  attach  the  declina- 
tion arm  in  place. 

(2)  To  set  the  vernier  of  the  declination  arc. — Set  the  declination 
vernier  to  read  approximately  zero,  and  bring  the  sun's  image  upon 
either  disk  as  in  an  orientation  to  the  meridian,  changing  the  eleva- 
tion of  the  polar  axis  as  may  be  necessary  to  bring  the  solar  line  of 
collimation  upon  the  sun.    With  the  sun's  image  accurately  between 
the  equatorial  lines,  clamp  all  other  motions  and  reverse  the  declina- 
tion arm  on  the  polar  axis,  thus  bringing  into  use  the  second  line 
of  collimation.     Note  if  the  image  of  the  sun  is  now  squarely  between 
the  second  pair  of  equatorial  lines;  if  not,  correct  half  the  differ- 


INSTRUMENTS  AND  METHODS.  85 

ence  by  movement  of  the  tangent  screw  of  the  declination  arc. 
Again  orient  in  azimuth  to  bring  the  sun's  image  accurately  between 
the  equatorial  lines,  clamp  and  reverse  as  before,  repeating  the  test 
until  satisfactory.  When  the  lines  of  collimation  have  thus  been 
made  truly  at  right  angles  to  the  polar  axis,  the  vernier  may  be  shifted 
to  read  zero  in  this  position. 

The  general  test  of  the  Burt  solar  compass,  by  comparing  its  indica- 
tions, resulting  from  solar  observations  made  during  a.  m.  and  p.m. 
hours,  with  the  true  meridian  determined  Ly  independent  method, 
is  similar  to  the  test  of  the  Smith  solar  attachment  except  in  respect 
to  the  test  of  the  latitude  arc.  No  provision  is  made  for  independent 
adjustment  of  the  latitude  arc,  and  in  the  operation  of  the  Burt 
solar  compass  the  latitude  is  used  as  given  by  the  instrument  resulting 
from  a  meridian  observation  on  the  sun.  In  this  respect  therefore 
the  noon  observation  with  the  Burt  solar  compass  differs  from  the 
noon  observation  with  the  Smith  solar  attachment. 

Example  of  noon  observation  with  the  Burt  solar  compass,  in  lati- 
tude 38°  53'  40"  N.,  and  longtitude  77°  01.  V  W.: 

"May  6,  1910:  At  this  station  I  set  off  16°  26'  N.,  on  the  decl.  arc; 
and,  at  apparent  noon,  observe  the  sun  on  the  meridian;  the  result- 
ing latitude  is  38°  54'  N." 

ERRORS    IN    AZIMUTH,    DUE    TO    SMALL    ERRORS    IN    DECLINATION    OR 
LATITUDE. 

83.  It  may  frequently  happen  with  a  solar  transit,  especially  at 
the  beginning  of  a  new  survey  or  with  an  instrument  insufficiently 
tested,  that  the  first  meridional  trials  are  made  with  slight  errors 
in  the  settings  of  the  latitude  and  declination  arcs,  resulting  in  small 
errors  in  azimuth.  This  may  be  particularly  true  with  a  solar 
compass  prior  to  a  determination  of  the  instrumental  latitude.  The 
correction  of  such  errors  has  been  provided  for  in  Table  22,  Standard 
Field  Tables,  which  may  be  applied  to  results  of  single  observations 
with  considerable  certainty,  .but  not  so  well  to  a  series  of  observations 
as  in  ordinary  line  work  owing  to  the  changing  values  (for  hours  from 
noon)  of  the  correction  coefficients.  The  explanation  with  the  table 
gives  a  key  to  the  direction  of  the  azimuth  errors  on  account  of  small 
errors  in  setting  the  latitude  and  declination  arcs. 

For  example,  at  9h40m  a.  m.,  app.  t.,  at  a  station  in  latitude  assumed 
to  be  46°  20X  N.,  a  test  was  made  with  a  solar  transit  whereby  the  trial 
indication  was  found  to  fall  0°  05X  west  of  the  true  meridian.  Sub- 


86 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


sequent  determinations  of  the  true  latitude  of  the  station  and  of  the 
correctness  of  the  vernier  of  the  declination  arc  showed  that  the 
actual  latitude  of  the  station  was  46°  21/.5  N.,  and  that  the  vernier 
of  the  declination  arc  had  an  index  error  which  gave  readings 
0°  OCK.5  S.  of  the  calculated  declination  (i.  e.  reading  15°  19'.5  N. 
for  a  calculated  declination  of  15°  2(X  N.).  Thus  in  the  test  the 
latitude  arc  was  set  lx.5  S.  of  the  correct  latitude  of  the  station,  and 
the  declination  arc  was  actually  set  0'.5  N.  of  the  value  that  would 
have  been  set  had  the  index  error  been  known. 

Table  22  is  entered  to  obtain  the  correction  coefficients: 


Latitude. 

Hours  from  noon. 

2hOm. 

2h  20^. 

8*1K 

45°  00' 
46    21.5 
50    00 

2.83 

2.55 
2  62 

2.00 

Declination       coeffi- 
cient. 

3.11 

2.81 

2.20 

45    00 
46    21.5 
50    00 

2.45 

2.10 
2.16 

1.41 

Latitude  coefficient. 

2.69 

2.31 

1.56 

The  corrections  are  then  applied  as  follows: 
Indication  of  solar  in  test      =S.  0°     OS'.O  W. 
Correction  for  declination      =      0       01  .3  E.=(2.62X0.5) 
Correction  for  latitude  =      0       03  .2  E. =(2.16X1-5) 


Corrected  indication  of  solar=S.  0°     OCX.5  W. 

The  above  corrections  will  often  serve  to  explain  the  apparent 
errors  of  the  solar,  but  these  are  not  intended  for  use  in  line  work, 
and  can  not  be  accepted  in  lieu  of  satisfactory  subsequent  tests 
based  on  correct  values. 

In  the  above  connection  it  should  be  explained  that  it  is  not 
deemed  desirable  to  burden  the  official  record  with  evidence  of 
correction  for  index  errors  found  in  the  verniers  of  the  latitude  and 
declination  arcs,  "other  than  to  state,  when  such  are  determined,  that 
the  same  are  forthwith  removed  or  are  allowed  for  in  subsequent 
observations. 

POLARIS    AT    ELONGATION. 

84.  The  surveyor  having  thoroughly  considered  the  theory  and 
use  of  the  solar  instrument  in  its  relation  to  the  public-land  surveys, 


INSTRUMENTS  AND  METHODS. 


87 


and  presumably  mastered  its  operation,  his  attention  is  now  directed 
to  the  approved  methods  of  observation  to  establish  the  true  meridian 
with  which  to  make  comparisons  of  the  indications  of  the  solar 
apparatus  as  a  necessary  test  of  such  an  instrument,  or  without  a 
solar  instrument,  the  establishment  of  the  true  meridian  from  which 
to  project  transit  lines  and  to  test  the  calculated  course  thereof. 

Of  the  various  independent  methods  of  observation  to  establish 
the  true  meridian,  the  simplest  and  most  reliable  is  found  in  the 
observation  upon  Polaris  at  eastern  or  western  elongation. 

Azimuth  of  Polaris  at  elongation: 


Sin 


_COS  5 

~cos  $ 


Zenith 


Observing 
station 


Diurnal  circle 


of  Polaris 


/  / 
/  / 
// 


fig.  13. 


1 


The  meridian  and  vertical  planes  tangent  to  the  diurnal  circle  of  Polaris  as  viewed 
from  outside  of  the  celestial  sphere. 


88 


MANUAL,  OF  SURVEYING  INSTRUCTIONS. 


Example  of  computing  the  azimuth  of  Polaris  at  elongation,  Octo- 
ber 20,  1910,  in  latitude  46°  20X  N.,  on  which  date  the  declination  of 
Polaris=88°49/4S//N.: 

log  cos  6=8.310033 
"    cos  0=9.839140 


"    sin  J.=8.470893 


A= Azimuth  of  Polaris  at  elongation=l°  41X  41X/. 

85.  A  table  of  azimuths  of  Polaris  at  elongation  for  latitudes  from 
25°  to  70°  N.,  appears  in  the  Ephemeris,  arguments:  declination  of 
Polaris,  and  latitude  of  station. 

Example  in  the  use  of  the  table  of  azimuths  of  Polaris  at  elongation, 
same  date  and  station  as  above,  showing  the  method  of  interpolation: 


Latitude. 

Declination. 

88°  49'  40" 

88°  49'  48" 

88°  49'  50". 

Azimuths  at  elongation. 

46°  00' 
46    20 
47    00 

1°  41'  15" 
1    43  08 

1°  41'  04" 
1    41   42 
1    42  57 

1°  41'  01" 
1    42  54 

By  interpolation  in  the  table  the  required  azimuth  of  Polaris 
at  elongation  is  therefore  found  to  be  1°  41'  42". 

86.  An  observation  upon  Polaris  at  elongation  for  azimuth  con- 
sists in  marking  upon  the  ground  a  point  to  define  the  true  line  of 
sight  to  Polaris  at  the  epoch  of  elongation,  from  which  to  lay  off  the 
true  meridian.     An  equivalent  process  is  to  determine  the  true 
horizontal  angle  by  deflection  from  a  fixed  reference  point  to  Polaris 
at  the  epoch  of  elongation,  by  which  to  determine  the  true  bearing 
of  the  reference  point. 

POLARIS  AT  ELONGATION,  OBSERVING  PROGRAM  "a." 

87.  Select  the  observing  station  and  make  suitable  provision  to 
mark  the  line  defining  the  direction  of  Polaris  at  elongation;  the 
flag  point  should  be  from  5  to  10  chains  N.  of  the  transit  point,  and 
should  be  cleared  of  all  obstruction  before  dark.     Determine  the 
local  mean  and  watch  time  of  elongation  of  Polaris,  provide  suitable 


INSTRUMENTS  AND  METHODS.  89 

illumination  for  both  the  transit  and  flag  point,  and  have  every- 
thing in  readiness  as  much  as  15  minutes  before  the  time  of  elonga- 
tion. 

Thoroughly  level  the  transit. 

About  six  minutes  before  elongation,  with  the  telescope  in  direct 
position,  bisect  Polaris,  note  the  watch  time,  and  mark  the  direction 
of  sight. 

Reverse  the  transit,  bisect  Polaris,  note  the  watch  time,  and  mark 
the  direction  of  sight. 

Again  level  the  transit. 

With  the  telescope  in  the  reverse  position  bisect  Polaris,  note  the 
watch  time,  and  mark  the  direction  of  sight. 

Reverse  the  transit  to  the  direct  position  of  the  telescope,  bisect 
Polaris,  note  the  watch  time,  and  mark  the  direction  of  sight. 

By  daylight  determine  the  mean  (a)  of  the  first  and  fourth  sights, 
and  (6)  the  mean  of  the  second  and  third  sights;  then  take  the  mean 
of  points  "a"  and  "6"  to  define  the  true  direction  of  Polaris 
at  elongation. 

The  mean  of  the  four  watch  readings  may  be  taken  as  the  watch 
time  of  observation,  which  if  within  four  or  five  minutes  of  correct 
watch  time  of  elongation,  the  mean  position  of  Polaris  during  the 
observation  will  be  within  1"  or  2"  of  true  elongation.  The  proper 
value  of  the  azimuth  of  Polaris  at  elongation  having  been  taken  from 
the  table  is  then  used  to  lay  off  the  true  meridian  to  the  east  for  west- 
ern elongation  or  to  the  west  for  eastern  elongation. 

The  above  program  practically  eliminates  instrumental  errors 
in  observation.  In  laying  off  the  azimuth  of  Polaris,  the  angle  may 
be  laid  off  directly,  if  desired,  checked  by  the  method  of  repetitions, 
and  corrected  if  necessary;  or  the  azimuth  angle  may  be  laid  off  by 
the  natural  tangent  method;  this  should  then  be  checked  by  reading 
the  angle  on  the  plates. 

Example  of  observation  of  Polaris  at  elongation,  observing  pro- 
gram "a:" 

55465° — 19 7 


90 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


Field  record. 


Final  field  notes. 


Sept.  10,  191 
of  Polaris, 
Red.  to  long 
Red.  to  lat. 

L.  M.  T.  of  3 
Watch  slow 

Watch  time 

I,  Gr.  E.  E. 
lat.  40° 
.  111°  45'  W. 
i3°22'30"N. 

u.  E.  of  Polaris. 

=  8h17.0mp.  m. 
=  -1.2 

=  +0.5 

86] 

s 
1 
i 
1 
8 
c 
e 
s 
t 
r 
t 
t 
(] 
5 

Az 
e 

»f 

a 

d 

8 

5 

...--8*] 

16.  3™  p.m. 
1.7 

ofl.m.t. 
ofE.  E. 

4.  6mp.  m. 

Telescope. 

Watch  Time. 

Direct- 

..  8*>OS» 

»  26"  p.  m. 
20 
34 

46 

Reversed 

8  11 

Reversed 

.  8  14 

Direct    .  . 

..  8  16 

Mean 

8M2< 

»  46"  p.  m. 

Declination  of  Polaris=88°  49'  54"  N. 

Latitude. 

Declination. 

88°  49'  50"     88" 

49'  54" 

88°  49'  60" 

Azimuth. 

43C  00'  00" 
43  22  30 
44   00  00 

1°  35'  57"      1 
1 
1    37  33         1 

»  35'  51" 
36  27 
37  27 

1°  35'  43" 
1    37  19 

Sept.  10,  1911,  in  camp  at  the 
standard  cor.  of  Tps.  1  N., 
Rs.  39  and  40  E.,  Boise  Her., 
in  latitude  43°  22'  30"  N.,  ancf 
longitude  111°  45'  W.,  at 
8h  16.3m  p.  m.f  i.  m.  t>>  i 
observe  Polaris  at  eastern 
elongation,  making  four  ob- 
servations, two  each  with 
the  telescope  in  direct  and 
reversed  positions,  and  mark 
the  mean  point  in  the  line 
thus  determined,  on  a  peg 
driven  firmly  in  the  ground, 
5chs.N. 

Azimuth  of  Polaris  at  eastern 
elong£tion=l°  36'  27". 

Sept.  11:  I  lay  off  the  azimuth  of 
Polaris,  1°  36'  30",  to  the  west, 
and  mark  the  meridian  thus 
determined,  by  a  tack  in  a  peg 
driven  firmly  in  the  ground> 
5  chs.  N. 


The  above  program  of  observatipn  of  Polaris  at  elongation  is  the 
most  convenient  method  where  there  is  an  opportunity  to  mark  the 
direction  of  the  line  of  sight.  Occasionally  conditions  obtain  where 
it  is  impossible  to  define  or  mark  the  direction  of  the  observation ; 
the  program  may  then  be  altered  to  the  reading  of  deflection  angles 
as  shown  in  the  next  method. 

POLARIS  AT  ELONGATION,  OBSERVING  PEOGRAM  "b." 

88.  Select  the  observing  station  and  mark  a  point  by  driving 
a  tack  in  a  peg  driven  firmly  in  the  ground  approximately  in  the 
true  meridian  as  determined  by  the  solar  before  sunset,  or  choose 
other  suitable  reference  mark  in.  any  direction.  The  reference 
point  should  not  be  nearer  to  the  transit  than  5  chains  distant.  Deter- 


INSTRUMENTS  AND  METHODS.  91 

mine  the  local  mean  and  watch  time  of  elongation  of  Polaris,  pro- 
vide suitable  illumination  for  both  the  transit  and  flag  point,  and 
have  everything  in  readiness  as  much  as  10  minutes  before  the  time 
of  elongation. 

Thoroughly  level  the  transit. 

About  6  minutes  before  elongation  with  the  transit  in  direct 
position,  read  and  note  the  deflection  angle  from  the  reference  point 
to  Polaris,  noting  ajso  the  watch  time  of  observation. 
•  Reverse  the  transit  and  read  and  note  the  deflection  angle  from 
the  reference  point  to  Polaris,  noting  also  the  watch  time  of  observa- 
tion. 

Again  level  the  transit. 

With  the  transit  in  the  reverse  position  again  read  and  note  the 
deflection  angle  from  the  reference  point  to  Polaris  and  note  the 
watch  time  of  observation. 

Reverse  the  transit  to  the  direct  position  and  again  read  and  note 
the  deflection  angle  from  the  reference  point  to  Polaris,  and  note 
the  watch  time  of  observation. 

As  the  position  of  Polaris  remains  within  about  0°  OCX  01"  of  true 
elongation  for  a  period  of  about  five  or  six  minutes  either  side  of  the 
time  of  exact  elongation,  the  observation  may  be  considered  satis- 
factory if  all  of  the  watch  readings  fall  within  the  stated  period. 

The  mean  of  the  four  horizontal  deflection  angles  may  be  taken 
to  which  must  be  applied  the  value  of  the  azimuth  of  Polaris  at 
Elongation  taken  from  the  table,  to  obtain  the  true  bearing  of  the 
reference  flag,  from  which  the  true  meridian  may  be  laid  off,  or  the 
flag  may  be  used  as  a  reference  point. 

A 'reference  point  in  any  direction  may  be  used  in  the  above 
method ;  the  direction  of  the  deflection  from  the  reference  point  to 
Polaris  should  always  be  clearly  stated.  The  insignificant  figures 
of  the  final  result  may  be  discarded  if  the  value  of  the  bearing  angle 
does  not  enter  into  another  determination  that  demands  great  pre- 
cision. In  the  example  below  the  true  meridian  may  be  laid  off  by 
accurately  measuring  a  distance  from  the  reference  point,  at  right 
angles  to  the  line  of  sight,  found  by  multiplying  the  distance  from 
the  instrument  to  the  reference  point  (660  ft.)  by  the  tangent  of  the 
bearing  angle  (nat  tan  0°  00'  44"  =--0.00021)  which  gives  0.14  ft. 
After  laying  off  the  true  meridian  the  angle  from  the  reference  point 
may  be  checked  by  the  method  of  repetitions. 


92 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


Example  of  observation  of  Polaris  at  elongation,  observing    pro- 
gram <  <6": 


Field  record. 


=6^  46.  lm  p.  m. 
=  -  1.1 
-  -  1.0 


Apr.  1, 1911,  Gr.  W.  E. 

of  Polaris,  lat.  40° 
Tied,  to  long.  104°  39'  W. 

"     "     lat.  46°  13'  N. 


L.  M.  T.  of  W.  E.  of  Polaris.      =6*  44.0">p.  m. 
Watch  slow  of  L.  M.  T.  =-2.9 


Watch  time  of  W.  E 


Telescope. 


Direct 

Reversed . 
Reversed . 
Direct 


Mean. 


Watch 
time. 


6h  37m  22» 
6  39  40 
6  43  14 
6  45  30 


6k  4im 


Deflection 
angle. 


1°41'00' 
1  40  30 
1  40  00 
1  40  30 


1°  40'  30' 


Declinationof  Polaris- 88°  49'  58"  N. 


Latitude. 


40°  00' 

46  13 

47  00 


Declination. 


88°  49'  50" 


88°  49'  58" 


88°  49'  60" 


Azimuth. 


1°  41'  01" 
1    42  54 


1°  40'  50" 
1    41  14 
1    42  42 


1°  40'  47' 
1    42  39 


Final  field  notes. 


April  1,  1911,  in  camp  at  the  cor. 
of  Tps.  5  and  6  N.,  Us.  56  and 
57  E.,  Prin.  Mer.,  Montana, 
in  latitude 46°  13'  N.,  and  longi- 
tude 104°  39'  W.,  at  6h  44.0» 
p.  m.,  1.  m.  t.,  I  observe  Polar- 
is at  western  elongation,  mak- 
ing four  observations,  two  each 
with  the  telescope  in  direct 
and  reversed  positions,  reading 
the  deflection  angle  from  a  tack 
in  a  peg  driven  firmly  in  the 
ground,  10  chs.  N.,  west  to 
Polaris: 

Azimuth  of  Po- 
laris at  west- 
em  elonga- 
tion =  1041'14" 

Mean  deflec- 
tion angle  =  1  40  30 

True  bearing  of 
mark 


89 .  Both  of  the  above  observing  programs  require  the  surveyor  to 
compute  in  advance  the  correct  watch  time  of  elongation,  and  in  so 
conducting  the  observation  the  minimum  period  is  consumed  in  the 
observing  program;  every  opportunity  is  also  thus  afforded  for  re- 
versals to  eliminate  instrumental  errors  and  otherwise  to  introduce 
creditable  refinement.  However,  should  the  watch  error  be  unknown , 
the  observation  may  be  conducted  by  following  the  motion  of  Polaris 
in  azimuth  during  an  ample  period  preceding  elongation  to  insure 
that  the  epoch  of  the  vertical  motion  of  Polaris  in  its  diurnal  circle, 


INS'lUUMENTH  AND  METHODS.  93 

or  zero  motion  in  azimuth,  is  taking  place,  when  the  surveyor  marks 
the  direction  of  sight  thus  defined. 

The  rate  of  horizontal  motion  for  the  hour  preceding  elongation 
rapidly  diminishes,  the  change  in  azimuth  being  to  the  west  for 
western  elongation,  or  to  the  east  for  eastern  elongation,  when  Polaris 
will  follow  the  vertical  cross- wire,  after  which  the  motion  is  reversed 
at  an  accelerating  rate.  This  suggests  a  third,  but  less  refined,  ob- 
serving program . 

POLARIS  AT  ELONGATION,  OBSERVING  PROGRAM  "C." 

00.  Select  the  observing  station  and  make  suitable  provision  to 
mark  the  line  defining  the  direction  of  Polaris  at  elongation;  provide 
suitable  illumination  for  both  the  transit  and  flag  point,  and  have 
everything  in  readiness  as  much  as  an  hour  before  the  time  of  elonga- 
tion. 

Thoroughly  level  the  transit. 

Bisect  Polaris  and  note  that  the  motion  of  the  star  carries  it  away, 
from  the  vertical  wire  in  the  proper  direction.  As  long  as  this  motion 
is  discernible  continue  the  bisection  of  Polaris  by  the  tangent  move- 
ment. When  it  can  not  be  discerned  in  a  period  of  several  minutes 
that  the  least  lateral  motion  is  taking  place  mark  the  direction  of 
sight  upon  the  ground. 

Reverse  and  level  the  transit. 

Again  bisect  Polaris  and  mark  the  direction  of  sight  upon  the. 
ground. 

Verify  the  position  of  Polaris  in  its  diurnal  circle  by  again  bisect- 
ing the  star  and  without  changing  the  tangent  motion  note  the  move- 
ment of  Polaris;  the  motion  should  still  be  nearly  vertical,  with  a 
scarcely  discernible  movement  in  the  opposite  horizontal  direction. 

By  daylight  determine  the  mean  of  the  sights,  and  establish  the 
meridian  by  properly  laying  off  the  correct  azimuth  as  described 
in  observing  program  "a." 

AZIMUTH   OP   POLARIS    AT   ANY    HOUR    ANGLE. 

01.  AVhile  no  more  reliable  method  is  at  the  command  of  the  sur- 
veyor for  the  establishment  of  the  true  meridian  than  the  observa- 
tion upon  Polaris  at  elongation,  yet  the  epoch  of  elongation  may 
occur  at  a  very  inconvenient  tune  and  should  Polaris  be  obscured 
by  clouds  at  the  time  of  elongation  the  observation  must  fail.    The, 
"hour  angle7'  method  admits  of  observation  upon  Polaris  for  azi- 
muth at  any  time  that  the  star  is  visible;  the  precise  watch  error 
local  mean  time  must  be  known,  but  if  this  has  been  determined, 


94  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

the  hour  angle  method  becomes  at  once  the  most  convenient.  The 
possible  accuracy  of  the  result  compares  favorably  in  every  way 
with  the  refinement  to  be  obtained  in  an  observation  at  elongation. 

The  determination  of  the  watch  error  local  mean  time  and  the  cal- 
culation of  hour  angles  having  been  fully  treated  on  previous  pages, 
it  remains  only  to  state  that  the  record  of  the  time  observation  should 
appear  in  the  field  notes  with  the  record  of  all  observations  upon 
Polaris  for  azimuth  by  the  hour  angle  method,  as  the  azimuth 
observation  is  incomplete  without  the  time  determination.  With 
the  meridian  observation  of  the  sun  for  apparent  noon,  and  the  use 
of  the  azimuth  tables  contained  in  the  Ephemeris,  the  entire  process 
becomes  so  simple  and  yet  so  highly  refined  that  the  surveyor  should 
early  become  thoroughly  familiar  with  the  hour  angle  method. 

92.  Azimuth  of  Polaris  at  any  hour  angle. — "£"=sidereal  hour 
angle  in  angular  measure;  in  hoar  angles  exceeding  90°  the  function 
"  — sin  <j>  cos  V  becomes  positive  by  virtue  of  the  cosine  of  an  angle 
between  90°  and  270°  being  treated  as  negative  in  analytical  reduc- 
tions: 

sin  t 

Tun    ^1  — i 

cos  <£  tan  5  —  sin  <f>  cos  t 

Example  of  computing  the  azimuth  of  Polaris,  February  23, 1911, 
at  a  mean  time  hour  angle  of  2h  37 .4m,  in  latitude  33°  2(X  N.,  on 
which  date  the  declination  of  Polaris=88°  50'  08"  N.: 
Mean  time  hour  angle          =2h37.4m 

=2h37m248    2h  =30° 

37m=  9°  15' 
Bed.  to  sidereal  hour  angle=      +26*  50*  =       12'  30" 

Sidereal  hour  angle  =2h37m5Qs         =39°27/30"[ 

log  cos  <t>  «  9. 921940    log  sin  $          =9.  739975 

"°  tan  5  =1. 691944     "  cos  t          =9. 887666 


"    cos  <£  tan  5=  1.  613884      "  sin  <£  cos  £=9.  62764] 
nat  cos  <£  tan  5=41. 104         nat  sin  <f>  cos  t=0. 424 
nat  sin  <£  cos  t—  0.424  (— ) 

log  sin  *  =9. 803127 

Algebraic  sum=40. 680  "  40.680         =1. 609381 

"  tan -4          =8. 193746 
Azimuth  of  Polaris  at  above  hour  angle,  J.=0°  53X  42" 


I N  STRU AIEX  TS  A N D  METHODS . 


95 


98.  A  table  of  azimuths  of  Polaris  at  all  hour  angles,  for  latitudes 
from  30°  to  50°  N.,  appears  in  the  Ephemeris,  arguments:  declina- 
tion of  Polaris,  mean  time  hour  angle,  and  latitude  of  station.  For 
other  than  the  latitudes  given  in  the  table  the  surveyor  will  be 
required  to  solve  the  above  equation. 

Example  in  the  use  of  the  table  of  azimuths  of  Polaris  at  any 
hour  angle,  same  date,  hour  angle  and  station  as  above,  showing 
the  method  of  interpolation: 


Declination. 

Latitude. 

88°  60'  0" 

88°  5<y  08" 

88°  50'  10" 

32°  (XX 

33°  2V 

34°  (MX 

Mean  time  hour  angles. 

Azimuths  of  Polaris. 

2h  34.7m 
41.1 

2»*  35.  1m 
37.4 
41.5 

2h  35.2m 
41.6 

52'.  2 
54.  0 

53'.  1 
53.  7 
54.  9 

53'.  5 
55.  3 

By  interpolation  in  the  table  the  required  azimuth  of  Polaris  is 
therefore  found  to  be  0°  53'.7=0°  53'  42". 

94.  Example  of  computing  the  azimuth  of  Polaris,  Sept.  11,  1911, 
at  a  mean  time  hour  angle  of  7h  25. lm,  in  latitude  42°  54'  N.,  on  which 
date  the  declination  of  Polaris=88°  49'  54"  N.: 


Mean  time  hour  anglp 

,=7h  25  lm 

7h  —105° 

Reduction  to  sidereal 

hour  angle... 

=7b  25m  068 
.=    -flm!38 

19s  = 

'30' 
4/45// 

Sidereal  hour  angle  

.=7h26m198 

=111° 

34X  45" 

j^._,___ 

log  cos  <f> 
"  tan  5 

=9.864833 
=1.  690496 

log  sin  0 

"     COS* 

=9 
=9 

.832969 
.  565596 

"  cos  <£  tan  6 

=1.  555329 

"   sin  <f>  cos 

t              =9 

.398565 

nat  cos  <£  tan  5 

=35.  919 

nat  sin  <b  cos 

t             = 

,250 

"   sin  <f>  cos  5 

-    .250(+) 

log  sin  t 

=9 

.968441 

Algebraic  sum 

=36.169 

11   36.169 

=1 

.558337 

"   tan  A 

=8 

.  410104 

Azimuth  of  Polaris  at  above  hour  angle,  A 


96 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


95.  Example  in  the  use  of  the  table  of  azimuths  of  Polaris  at  any 
hour  angle,  same  date,  hour  angle  and  station  as  above: 


Declination. 

Latitude. 

88°  49'  50" 

88°  49'  54" 

88°  49'  60" 

42°  (XX 

42°  54' 

44°  00/ 

Mean  time  hour  angles. 

Azimuths  of  Polaris. 

7*  15.  7m 
29.3 

7*  15.1m 
25.1 

28.8 

7fc  14.2^ 
28.0 

88'.  6 
86.  6 

89  '.9 
88.  4 
87.  8 

91  '.5 
89.  4 

By  interpolation  in  the  table  the  required  azimuth  of  Polaris  is 
therefore  found  to  be  88X.4=1°  28'  24". 

96.  An  observation  upon  Polaris  for  azimuth  by  the  hour  angle 
method  consists  in  marking  upon  the  ground  a  point  to  define  the 
true  line  of  sight  to  Polaris  at  any  convenient  epoch,  the  watch  error 
local  mean  time  being  known,  from  which  line  to  lay  off  the  true 
meridian.     An  equivalent  process  is  to  determine  the  true  hori- 
zontal angle  by  deflection  from  a  fixed  reference  point  to  Polaris  at 
any  convenient  epoch,  the  watch  error  local  mean  time  being  known, 
by  which  to  determine  the  true  bearing  of  the  reference  point. 

HOUR    ANGLE    OBSERVATION    OF    POLARIS,    OBSERVING    PROGRAM    utt.M 

97.  Select  the  observing  station  and  make  suitable  provision  to 
mark  the  line  defining  the  direction  of  Polaris;  the  flag  point  should 
be  from  5  to  10  chains  north  of  the  transit  point;  provide  suitable 
illumination  for  both  the  transit  and  flag  point. 

Thoroughly  level  the  transit. 

With  the  telescope  in  the  direct  position,  bisect  Polaris,  note  the 
watch  time,  and  mark  the  direction  of  sight. 

Reverse  the  transit,  bisect  Polaris,  note  the  watch  time,  and 
mark  the  direction  of  sight. 

Again  level  the  transit. 

With  the  telescope  in  the  reverse  position  bisect  Polaris,  note  the 
watch  time,  and  mark  the  direction  of  sight. 

Reverse  the  transit  to  the  direct  position  of  the  telescope,  bisect 
Polaris,  note  the  watch  time,  and  mark  the  direction  of  sight. 

By  daylight  determine  the  mean  (a)  of  the  first  and  fourth  sights, 
and  (6)  of  the  second  and  third  sights;  then  take  the  mean  of 


I N  STK U  ME N  TS  A !N  D  METHODS. 


97 


points  "a"  and  "6"  to  define  the  true  direction  of  Polaris  at  the 
epoch  of  the  average  of  the  watch  times  of  observation. 

Treat  the  reduction  as  one  observation,  applying  the  watch  error 
to  the  average  watch  time  of  observation  to  obtain  the  correct  local 
mean  time  of  observation. 

Enter  the  table  in  the  Ephemeris  or  make  the  computation  to 
determine  the  value  of  the  azimuth  of  Polaris  at  the  epoch  of  the 
observation  with  the  stated  arguments:  declination  of  Polaris, 
mean  time  hour  angle  and  latitude ;  this  value  is  then  used  to  lay  off 
the  true  meridian  to  the  east  if  Polaris  is  observed  west  of  the  meri- 
dian or  to  the  west  if  Polaris  is  observed  east  of  the  meridian. 

Example  of  hour  angle  observation  of  Polaris,  observing  program 
"a": 


Field  record. 


Meridian  observation  of  the  sun  for  apparent  noon: 

0=37°  18'  N.  90°  00' 

5=  4   36  S.  41    54 


y=48°  06' 

Watch  time. 
=  12*  00<"  IS* 

=  12   02    26 


0+6=41°  54' 
Sun's  W.  limb      O  - 

Watch  time  of  app.  noon 
App.  noon  =  12^  00"»  00s 

Equation  of  time  =  —11    25 

L.  M.  T.  of  apparent  noon 

Watch  fast  ofl.  m.  t. 

Hour  angle  observation  of  Polaris: 


22« 


12oi  47" 


Telescope. 


Watch  time. 


Direct 

Reversed. 
Reversed. 
Direct 


Mean 

Watch  fast  ofl.  m.  t.. 


L.  M.  T.  of  obsn. 


5*i  48^40"  p.  m. 
5    49    49 
5   51    36 
5   52    54 


5»i  50^  45»  p.  m. 
-  12    47 


37^  58*  p.  m. 
38.  0^  p.  m. 


Final  field  notes. 


Oct.  5, 1910,  in  camp  at  the  cor. 
of  sees.  5,  6.  31,  and  32,  on  the 
S.  bdy.  of  T.  31  S.,  K.  42  W.. 
6th  Prin.  Mer.,  Colo.,  in  lati- 
tude 37°  17'.6  N..  and  longi- 
tude 102°  11'  W.,  I  make  a 
meridian  observation  of  the 
sun  for  apparent  noon: 

Watch  time  of  obsn.=12h  01™ 

22^. 
Watch  fast  of  1.  m.  t.=12™  47*. 


At  the  same  station,  at  5*»  38.0m 
p.  in.,  1.  m.  t.,  I  make  an  hour 
angle  observation  on  Polaris 
east  of  the  meridian,  making 
four  observations,  two  each' 
with  the  telescope  in  direct 
and  reversed  positions,  and 
mark  the  mean  point  in  the 
line  thus  determined,  on  a  peg 
driven  firmly  in  the  ground, 
Schs.N. 


98 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


Field  record,  con. 


Gr.  U.  C.  of  Polaris,  Oct.  6,  1910    =0^  32.7°'  a.  m. 
lied,  to  long.  102°  11'  W.  —  —  1.1 

L.  M.  T.,  U.  C.  of  Polaris,  Oct.  6=»  0^  31.6™  a.  m. 

+12 
L.  M.  T.  of  obsn.,  Oct.  5  =5   38.0    p.  m. 

Hour  angle  of  Polaris  east  of  the 
meridian  -=  6&  53.6^ 

Declination  of  Polaris=S8°  49'  42"  N. 


Final  lield  notes,  con. 


Declination. 


+88°  49' 


40" 


42" 


50* 


Mean  time  hour  angles. 


6^51. 6« 
61.5 


53.6 
61.1 


6M9.5™ 
59.6 


Latitude. 


36°  00' 


37°  18' 


38°  00' 


Azimuth  of  Polaris. 


84'.  3 
83.  3 


85'.  7 
85.  5 

84.  8 


86'.  5 
85.  6 


Watch  time  of  obsn.,  mean  of 
four  readings=»  5>»  50°»  45«  p.  m. 


Oct.  6, 1  lay  oft  the  azimuth  of 
Polaris,  1°  25'  30",  to  the  west, 
and  mark  the  meridian  thus 
determined,  by  a  tack  in  a  peg 
driven  firmly  in  the  ground, 
8  chs.  N. 


HOUR  ANGLE  OBSERVATION  OF  POLARIS,  OBSERVING  PROGRAM   "6." 

98.  Select  the  observing  station  and  choose  a  suitable  reference 
mark  in  any  direction.  The  reference  point  should  be  at  least  5 
chains  distant. 

Thoroughly  level  the  transit. 

With  the  telescope  in  the  direct  position,  read  and  note  the  hori- 
zontal angle  from  the  reference  point  to  Polaris,  noting  the  watch 
time  at  the  moment  Polaris  is  properly  bisected. 

Reverse  the  transit  and  read  and  note  the  horizontal  angle  from 
the  reference  point  to  Polaris,  noting  the  watch  time  at  the  moment 
Polaris  is  properly  bisected. 

Again  level  the  transit. 

With  the  telescope  in  the  reverse  position  again  read  and  note  the 
horizontal  angle  from  the  reference  point  to  Polaris,  noting  the 
watch  time  at  the  moment  Polaris  is  properly  bisected. 

Reverse  the  transit  to  the  direct  position  of  the  telescope  and  again 
read  and  note  the  horizontal  angle  from  the  reference  point  to  Polaris, 
noting  the  watch  time  at  the  moment  Polaris  is  properly  bisected. 

Treat  the  reduction  as  one  observation,  applying  the  watch  error 
to  the  average  watch  time  of  observation  to  obtain  the  correct  local 


INSTRUMENTS  AND  METHODS. 


99 


The  mean  of  the  four  horizontal  deflection  angles  may  be  taken, 
to  which  must  be  applied  the  proper  value  of  the  azimuth  of  Polaris 
at  the  mean  epoch  of  the  observation,  to  give  the  true  bearing  of  the 
reference  flag,  from  which  the  true  meridian  may  be  laid  off,  or 
the  flag  may  be  used  for  a  reference  point. 

Example  of  hour  angle  observation  of  Polaris,  observing  program 


Field  record. 

Final  field  notes. 

Hour  angle  observation  on  Polaris: 

March  21  ,  1910,  at  a  transit  point 
in  Washington.  D.  C.,  hi  lati- 
tude 38°  537  40'  'N.f  and  longi- 
tude 77°  1'.6  W.,  I  find  by 
comparison  with  a  Western 
Union  telegraph  clock  that 
my  watch  is  1m  22*  slow  of 
75th  meridian  standard  time. 
At  the  same  station  at  6**  19.9m 
p.  m.,  1.  m.  t.,  I  make  an 
hour  angle  observation  on 
Polaris,  west  of  the  meridian, 
two  each  with  the  telescope 
in  direct  and  reversed  posi- 
tions, reading  the  horizontal 
deflection  angle  from  a  flag 
pole  about  20  chs.  S.,  in  the 
direction  S-W-N  to  Polaris. 
Watch  time  of  obsn.=-6*  26» 
403  p.  m. 
Mean  horizontal  angle 
from    Polaris    to 
•     flag         =177°  34'  15"  N-W-S 
Azimuth 
of  Polaris-     1   26  24    W. 

Horizontal  angle 
Telescope.          from   flag   to 
Polaris. 

Watch  time. 

Direct... 

177°  3 

4'  30" 
4   30 
4  00 
4   00 

6^  22m  373  p.  m. 
6    25    29 
6    28     17 
6    30     17 

Reverse* 
Reversed 
Direct... 

177    3 

177    3 

177    3 

Me 
Watch  si 
ard  tirr 
Correctio 
L.  M.  T. 

Gr.  U.  C 
same 
Bed.  to  1 
77°  1 

Hour  an 
theme 

Declinati 

an.  .  .          177°  34'  15" 
ow  of  75th  mer.  stand- 
le 
n  for  longitude  

Qh  26m  4Q3  p.  m. 

-f    1     22 
-86 

of  obsn.  Mar.  21, 

of  Polaris, 
date  =1*33 
ong. 
6'  W  «  -  0 

1910- 

6h  19m  56a 

6h  19.  901  p.  m. 
.Qmp.  m. 
.0=1  32.1     p.m. 

?le  of  Polaris  west  of 
idian                             •= 

on  of  Polaris 

4*  47.8m 

•88*  49'  41"  N. 

True  bear- 
ing     of 
flag    f*  N.  179*  OO;  3d^  W. 

Declination, 

Latitude. 

88°  49' 

38°  00' 

38*54'    40*00' 

40" 

11"         50" 

Mean  time  hour  angles. 

Azimuths  of  Polaris. 

&  33.  om 
49.0 

33.  7««      35.  0<* 
47.8 
49.  2        50.  8 

83'.  6 
85.5 

84'.  7       86'.  0 
80.4 
86  .  6       88  .  0 

100  MANUAL  or  SURVEYING  INSTRUCTIONS. 

POLARIS    AT   SUNSET   OR    SUNRISE. 

99.  Polaris  is  conveniently  observed  for  azimuth  by  the  hour 
angle  method  at  sunset  or  sunrise  without  artificial  illumination. 
The  preparation  for  the  observation  consists  in  computing  in  advance 
the  approximate  settings  in  azimuth  and  altitude  in  order  to  find 
Polaris,  and  the  plan  contemplates  an  approximate  reference 
meridian:  With  the  time  of  sunset  or  sunrise  assumed  as  the  time  of 
observation,  the  hour  angle  "t"  and  azimuth  "A"  are  ascertained 
in  order  to  find  the  position  of  Polaris  in  azimuth;  the  position  in 
altitude  is  found  by  the  following  approximation,  the  positive  sign 
being  used  for  hour  angles  less  than  6  hours  and  the  negative  sign 
for  hour  angles  exceeding  6  hours: 

?'^4>±70/  cos  t 

Example  of  computation  of  the  position  of  Polaris  at  sunset,  May 
6, 1911,  at  a  station  in  latitude  47°  20'  N.,  and  longitude  102°40/  W. : 

From  the  Ephemeris  the  declination  of  the  sun  is  found  to  be 
16°  18'  X.,  and  by  entering  Table  17,  of  the  Standard  Field  Tables, 
the  apparent  time  of  sunset  is  found  to  be  7M5m  p.  m. 

Assumed  time  of  obsn.,  May  6,  1911  7h  15m      p.  m. 

Gr.  U.  C.  of  Polaris,  May  6      =     10h  33.  5m  a.  m.     +12 

Red.  to  long.  102°  W  W.  -1.1  =       10   32. 4      a.  m. 


Assumed  hour  angle  of  Po- 
laris west  of  the  meridian  =        8h  42.  6m 
Hour  angle,  angular  measure  =     130°  39' 
Azimuth  of  Polaris,  W.  ^         1°  17' 
Latitude  of  station                 =47°  20'  ===== 
70'  cos  £=70  cos  130°  39X      =         46(-) 


34' 


Example  of  computation  of  the  position  of  Polaris  at  sunset,  Nov. 
6,  1911,  at  a  station  in  latitude  47°  20'  N.,  and  longitude  102°  4(K  W. : 

From  the  Ephemeris  the  declination  of  the  sun  is  found  to  be 
15°  44'  S.,  and  by  entering  Table  17,  of  the  Standard  Field  Tables, 


INSTRUMENTS  'AND  MiyJ5l€\2)S. 


101 


the  apparent  time  of  sunrise  is  fcand/tO  be 

4h  48m  p.  m. 

Gr.  U.  C.  of  Polaris,  Nov.  6,  1911 

Red.  to  long.  102°  4(K  W. 

L.  M.  T.  of  U.  C.  of  Polaris 
Assumed  time  of  observation 


==l(^  28.  2 
-       -1.  1 

=10*  27.  l 

=4    48 


p.  m. 


p.  m. 
p.  m. 


Assumed  hour  angle  of  Polaris  east  of  the  meridian=  5h  39.1m 
Hour  angle,  angular  measure  =84°  46' 

Azimuth  of  Polaris,  E.  ^  1°  43' 

Latitude  of  station  =47°  2(X 

70'  cos  f=*70  cos  84°  46X  =         06  (  +  ) 


26X 


Example  of  computation  of  the  position  of  Polaris  at  sunrise, 
November  7,  1911,  and  same  station  as  above: 

(       7h  12m  a  m 
Assumed  time  of  obsn.,  Nov.  7,  1911  ~<  ,    9 

L.  M.  T.  of  U.  C.  of  Polaris,  Nov.  6  =10  27.1  p.  m. 

Assumed  hour  angle  of  Polaris  west  of  the  meridian  =  8h  44.  9m 

Hour  angle,  angular  measure                                    =  131°  14r 

Azimuth  of  Polaris,  W.                                              ^  1°  16X 

Latitude  of  station          =47°20/  ===== 
70X  cos  £=70  cos  ISl0!^^       46(-) 


Thus  at  the  above  station  in  latitude  47°  20X  N.,  and  longitude 
102°  407  W.,  to  observe  Polaris  by  the  daylight  method  an  approxi- 
mate meridian  should  be  established  with  the  solar  before  sunset, 
then  to  find  Polaris  the  following  angles  are  set  off: 


Horizontal 
angle. 

Vertical 
angle. 

SunmtMaye.  191  1  ., 

1°17'  W. 

46°  34' 

Sunset  Nov.  6,  1911  

1°43'  E 

47°  26' 

Sunrise  Nov.  7,  1911  .... 

1°16'  W 

46*  34' 

102  >jLANUA]L  GF  3U&VJSYING  INSTRUCTIONS. 

The  abui  o  "/sorting^"  are  merely. approxiniations,  but  sufficiently 
close,  however,  to  bring  Polaris  reasonably  near  the  center  of  the 
field  of  the  telescope  where  the  star  will  be  found  in  plain  view; 
the  telescope  should  be  focused  upon  a  distant  object,  otherwise, 
though  Polaris  may  be  practically  at  the  center  of  the  field,  it  might 
be  out  of  focus  and  therefore  not  observable  during  daylight.  When 
Polaris  has  been  found  the  above  settings  have  answered  their 
purpose  and  the  observation  may  proceed  in  accordance  with  either 
observing  program  "a"  or  "6"  of  the  hour  angle  method,  the  final 
reductions  to  be  based  upon  the  precise  details  of  the  observation. 
During  the  reversals  of  the  transit  the  settings  should  be  made  each 
time.  The  daylight  hour  angle  method  is  particularly  desirable  be- 
cause the  observation,  including  all  instrumental  work,  marking  of 
points  upon  the  ground,  etc.,  is  accomplished  without  artificial  illu- 
mination, and  sunset  is  usually  a  convenient  time  to  devote  to  this 
field  duty. 

To  recapitulate,  the  following  general  program  will  be  found  best 
adapted  to  the  requirements  of  public-land  surveying  practice,  and 
will  be  used  most  extensively: 

Time:  By  meridian  observation  of  the  sun  for  apparent  noon. 

Latitude:  By  meridian  altitude  observation  of  the  sun. 

Azimuth,  true  meridian  upon  which  to  test  the  solar  apparatus: 
By  hour  angle  observation  on  Polaris  at  sunset. 

Azimuth,  on  line:  By  the  solar  transit  properly  adjusted  to  the 
true  meridian. 

ALTITUDE    OBSERVATION    OF   THE    SUN    FOR   AZIMUTH. 

% 

100.  While  the  methods  of  observation  upon  Polaris  for  azimuth 
are  unquestionably  the  most  desirable  in  their  relation  to  the  theory 
and  practice  of  public-land  surveying,  yet  a  very  efficient  alternative 
is  found  in  direct  altitude  observations  upon  the  sun  for  azimuth, 
with  a  number  of  equations  at  the  disposal  of  the  surveyor  to  suit  his 
convenience.  During  the  shorter  days  of  the  year  and  even  quite 
often  at  any  season  the  surveyor  finds  himself  at  a  loss  for  time  and 
suitable  daylight  hours  in  which  to  make  the  required  tests  of  his 
solar  attachment;  conditions  obtain  making  the  required  tests 
impossible  if  limited  to  a  Polaris  meridian  in  camp,  without  involv- 
ing unreasonable  delay.  It  is  in  such  cases  that  a  direct  altitude 
observation  upon  the  sun  for  azimuth,  on  the  actual  line  of  the 
survey,  finds  its  most  useful  application.  Presuming  the  surveyor 


INSTRUMENTS  AND  METHODS.  103 

at  .work  with  a  standard  instrument  with  solar  attachment,  the 
accuracy  of  its  adjustments  can,  by  this  method,  be  readily  tested 
at  work  on  line  at  any  suitable  morning  or  afternoon  hour,  without 
appreciable  loss  of  time.  Under  working  conditions  any  line  deter- 
mined with  the  solar  attachment  may  be  used  for  reference  pur- 
poses, while  vertical  and  horizontal  angles  are  recorded  to  the  sun 
to  obtain  the  necessary  data  for  computing  the  true  bearing  of  the 
established  solar  line.  A  series  of  three  altitude  observations  upon 
the  sun,  each  with  the  telescope  in  direct  and  reversed  positions, 
are  required  to  guard  against  error;  these  are  readily  made  in  10 
or  12  minutes,  while  the  reductions  may  be  made  in  the  evening 
without  loss  of  time  from  the  line  work. 

Other  difficulties  in  the  nature  of  temporary  disability  of  the  solar 
attachment,  and  cloudy  nights  preventing  Polaris  observations, 
or  other  adverse  conditions  may  sometimes  obtain,  during  which 
periods,  even  for  a  few  days,  if  the  surveyor  is  familiar -with  the 
method  of  direct  altitude  observation  upon  the  sun  for  meridian. 
Le  can  thus  establish  his  lines  and  possibly  realize  a  saving  of  the 
entire  time  of  his  party  until  the  trouble  is  removed.  To  the  sur- 
veyors who  have  used  this  method  little  more  needs  to  be  said  in  its 
favor,  but  to  those  unfamiliar  with  it  the  suggestion  is  made  to 
practice  the  observations  and  reductions  until  proficiency  is  attained, 
and  in  its  application  the  reward  will  come  many  times  during  an 
average  season's  work. 

Referring  to  the  description  of  the  standard  instrument  adopted 
by  the  General  Land  Office  it  will  be  noted  that  it  is  equipped  with 
a  full  vertical  circle,  a  colored  glass  shade  in  the  dust  shutter  of 
the  eye-piece,  and  a  prismatic  eye-piece;  these  are  essential  to  rapid 
and  accurate  altitude  observations  upon  the  sun. 

101.  An  altitude  observation  of  the  sun  for  azimuth  consists  in 
the  simultaneous  determination  of  the  true  vertical  and  horizontal 
angles  to  the  sun's  center,  the*  horizontal  angle  being  referred  to  a 
fixed  point.  With  the  true  vertical  angle  to  the  sun's  center,  the 
declination  of  the  sun,  and  the  latitude  of  the  station  all  known,  one 
of  the  following  equations  is  entered  and  a  calculation  made  of  the 
azimuth  of  the  sun's  center  at  the  epoch  of  observation,  as  referred 
to  the  true  meridian;  the  relation  between  the  sun's  calculated 
azimuth  and  the  recorded  angle  to  the  sun's  center  gives  the  true 
bearing  of  the  fixed  reference  point. 


104  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

102.  Altitude  observation  of  the  sun  for  azimuth. — Reverse  the  signs 
of  " 5"  for  south  declinations: 


l=    / 

V 


cos  \  (r-4>-5)  sin  \  (r- 

The  spherical  angles  "f  ",  "0",  and  "6"  appear  in  this  equation 
combined  as  in  the  formula  for  the  reduction  of  an  altitude  observa- 
tion of  the  sun  for  apparent  time,  and  when  it  is  desired  to  reduce 
for  both  time  and  azimuth,  the  above  equation  for  azimuth  is  to  be 
preferred  to  any  that  follow. 

103.  Altitude,  observation  of  the  sun  for  azimuth.  —  For  south  declin- 
ations the  function  "sin  5"  becomes  negative  by  virtue  of  the  sine 
of  a  negative  angle  being  treated  as  negative  in  analytical  reduc- 
tions: If  the  algebraic  sign  of  the  result  is  positive  the  azimuth  "A" 
is  referred  to  the  north  point,  but  if  negative,  the  azimuth  "  A"  is 
referred  to  the  south  point: 

Cos 


The  above  equation  is  very  convenient  in  reducing  for  azimuth 
only. 

104.  Altitude  observation  of  the  sun  for  azimuth.  —  To  many  sur- 
veyors the  following  equation  is  familiarly  expressed  directly  in 
terms  of  the  spherical  triangle  "pole-zenith-sun:  "  Reverse  the  sign 
of  "5"  for  south  declinations: 

Pole  to  zenith  =90°-<£=  colat.; 
Pole  to  sun       =90°  —5=  coded.  ; 
Zenith  to  sun  =90°—/&  =  coalt.; 
S—$  sum  of  the  three  side?: 


r     i  A—    Mn  S  gin  (£-- coded.) 
~ V    sin  colat.  sin  coalt. 


OBSERVING  PROGRAM,   MORNING. 


105.  Thoroughly  level  the  transit. 

With  the  telescope  in  direct  position  observe  and  record  the  hori- 
zontal deflection  angle  from  a  fixed  reference  point  to  the  sun's  right 
limb,  and  the  vertical  angle  to  the  sun 'supper  limb;  these  observa- 
tions must  be  simultaneous,  at  the  epoch  of  which  the  sun  will  appear 
as  indicated;  note  the  watch  time  at  the  epoch  of  the  observation:  <j  - 

Reverse  the  transit. 


INSTRUMENTS  AND  METHODS.  105 

Observe  and  record  the  horizontal  deflection  angle  from  the  fixed 
reference  point  to  the  sun's  left  limb,  and  the  vertical  angle  to  the 
sun's  lower  limb;  these  observations  must  be  simultaneous,  at  the 
epoch  of  which  the  sun  will  appear  as  indicated;  note  the  watch 

time  at  the  epoch  of  the  observation:  ~p 

The  mean  observed  vertical  and  horizontal  angles,  and  the  mean 
watch  time  are  to  be  used  in  the  reduction;  this  program  constitutes 
one  complete  altitude  observation,  which  is  repeated  until  a  series 
of  three  complete  direct  and  reversed  observations  are  made. 

OBSERVING  PROGRAM,  AFTERNOON. 

106.  In  the  afternoon  the  program  is  modified  only  as  to  the  order 
in  which  the  sun's  limbs  are  observed,  which  is  as  follows: 

First  observation,  telescope  direct,  observe  the  sun's  right  and 
lower  limbs:  £)- 

"     Second  observation,  telescope  reversed,  observe  the  sun's  left  and 
upper  limbs:  -fc 

107.  By  the  above  observing  programs  the  horizontal  and  ver- 
tical angles  in  the  direct  positions  of  the  telescope  will  be  found  of 
about  the  same  numerical  values  as  in  the  reversed  position  of  the 
telescope,  by  reason  of  the  sun  passing  in  a  direction  that  will  carry 
it  across  the  field  of  the  telescope  during  the  time  taken  in  the  re- 
versal and  second  setting.     Differential  refraction  is  therefore  prac- 
tically eliminated,  and  it  is  desirable  that  the  corresponding  angles 
in  the  direct  and  reversed  positions  of  the  telescope  be  about  the 
same  rather  than  as  far  apart  as  would  result  in  any  other  observing 
program. 

The  most  suitable  hour  for  this  observation  is  when  the  sun  is 
moving  rapidly  in  altitude  as  compared  with  a  Relatively  small 
change  in  azimuth.  When  the  sun  has  been  brought  into  about  the 
proper  position  in  the  field  of  the  telescope  the  observer  by  lateral 
motion  of  the  horizontal  tangent  screw  on  the  plates  keeps  the  vertical 
wire  tangent  to  the  sun's  right  or  left  limb  while  the  upper  or  lower 
limb  of  the  sun  by  the  direction  of  its  motion  gradually  approaches 
the  horizontal  wire ;  at  the  epoch  of  proper  taugency  of  the  two  limbs 
to  the  two  wires  the  observation  is  completed  by  calling  "  time  "  and 
stopping  all  motion  until  the  angles  are  recorded.  It  is  very  helpful 
for  an  assistant  to  read  the  time  and  to  enter  all  records. 
55465°— 19 8 


106 


MANUAL,  OF  SURVEYING  INSTRUCTIONS. 


108.  Example  of  direct  altitude  observation  of  the  sun  for  azi- 
muth, sun  north  declination,  and  both  north  and  south  of  an  east 
and  west  line: 

Final  field  notes. 

Aug.  2,  1909,  at  the  cor.  of  Tps.  31  and  32  S.,  Rs.  43  and  44  W., 
6th  Prin.  Her.,  Colo.,  in  latitude  37°  17'.5  N.,  and  longitude  102° 
18'.6  W.,  at  7h  30m.  a.  m.,  app.  t.,  I  set  off  37°  17'  30"  N.,  on  the  lat. 
arc;  17°  52'  N.,  on  the  decl.  arc;  and  determine  a  meridian  with  the 
solar,  whence  I  turn  90°  to  the  east  and  set  a  flag,  about  20  chs. 
dist. ;  then  to  test  this  indication  of  the  solar  I  make  a  series  of  three 
altitude  observations  of  the  sun  for  azimuth,  each  with  the  telescope 
in  direct  and  reversed  positions,  observing  opposite  limbs  of  the  sun, 
and  reading  the  horizontal  deflection  angles  from  the  flag  to  the  sun: 


Obser- 
vation. 

Telescope. 

Sun. 

Watch  time. 

Vertical 
angle. 

Horizontal  angle 
from  flag  to  sun. 

1st 

Direct  

r4- 

7*  36°»  54. 

30°  05' 

0°  08'  30"  to  N. 

k< 

Reversed... 

d 

-p 

7    38    15 

29    48 

0    33   00     "  " 

Mean  . 

29°  56'  30" 

0°  20'  45"  to  N. 

2nd 

Direct  

I. 

7h  4im  20* 

30°  58'  00  " 

0°  32'  00"  to  S. 

Reversed... 

d 

-p 

7    43    00 

30    46    30 

0    12   30     "  " 

Mean.  . 

30°  52'  15" 

0°  22'  15"  to  S. 

3rd 

it 

Direct  
Reversed... 

Q~ 

-p 

7*  52=»  00« 
7    53     48 

33°  05'  00" 
32    53   30 

2°  11'  00"  to  S. 
1    50   00     "  " 

Mean 

7h  52™  54« 

32°  59'  15" 

2°  00'  30"  to  S. 

By  1st  obsn.  flag  bears  N.  89°  58'  57"  E. 
By  2nd  obsn.  flag  bears  N.  89  58  26  E. 
By  3rd  obsn.  flag  bears  N.  89  58  38  E. 

Mean  true  bearing  of  flag  N.  89°  58'  40//  E. 
Indicated  error  of  solar 
attachment  1'  20" 


Field  record. 

The  declination  of  the  sun  for  the  mean  period  of  the  three  obser- 
vations=17°  51'  04"  N. 


INSTRUMENTS  AND  METHODS.  107 

The  following  reductions  are  made  to  obtain  the  true  vertical 
angles  of  the  above  observations: 


1st  obsn. 

2nd  obsn. 

3rd  obsn. 

v         =29°  56'  30" 

30°  52'  15" 

32°  59'  15" 

Refraction  =      —1  40 

-1   36 

-1   28 

Parallax      =      -j-       8 

+       8 

+       8 

h          =29°  54'  58" 

30°  50'  47" 

32°  57'  55" 

The  following  examples  of  reduction  are  all  by  the  equation : 

Cos  A= — ~ r  —tan  <t>  tan  h 

cos  0  cos  h 

log  cos  0=9.  900674  log  sin  6=9. 486493(+)  log  tan  0=9.  881708 
11  cos  7i=9.  937897  "   tan  A=9.  759970 


9.838571  9.838571        log  9.641678 

log         9.647922        nat(-)          .43821 
nat  (+)  .44455 
(-)  .43821 

cos^L=(+)  .00634 

-4=True  bearing  of  sun   =N.  89°  38X  12"  E. 
Angle  from  sun  to  flag      =(+)  0    2045 


True  bearing  of  flag          ==N.  89°  58X  57"  E. 

log  cos  0=9.  900674  log  sin  5=9. 486493(+)  log  tan  0=9.  881708 
"   cos  /i=9.  933763  "  tan  A=9.  776132 


9.834437  9.834437  log         9.657840 

log     9.652056  nat(-)   .45482 

nat(+).  44880  (+)   .44880 

cos^=(-)   .00602 

4=True  bearing  of  sun   =S.   89°  39X 19"  E. 
Angle  from  sun  to  flag      =(-{-)  0    22   15 

True  bearing  of  flag          =S.  90°  Olx  34"  E. 
=N.  89°  58'  26"  E. 


108  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

log  cos  <£=9.  900674  log  sin  5=9.  486493(-f )  log  tan  0=9.  881708 


=9.  923762 

9.  824436 

'  tan  £=9.  811941 

9.  824436 

log    9.  693649 

nat  (-)  .49391 
(+)  .45926 

log    9.  662057 
nat  (+).  45926 

cos^=(-)    .03465 

^l=True  bearing  of  sun    =S.  88°  00'  52"  E. 
Angle  from  sun  to  flag      =(+)2    0030 

True  bearing  of  flag          =S.  90°  01'  22"  E. 
=N.  89°58/38//E. 

The  particular  convenience  of  the  above  equation  is  noted  in  the 
fact  that  the  functions  "cos  <£",  "tan  <£",  and  "sin  6"  are  constant 
throughout  the  entire  reduction,  the  function  "A"  being  the  only 
variable. 

109.  The  third  of  the  above  series  is  selected  for  an  example  of 
reduction  by  the  equation:  

Co  i  A—    /-^  ^  sin  (8— coded.) 
V  sin  colat.  sin  coalt. 

90° -0=90° -37°  17'  30"        =52°  42'  30"=colat. 
90°-S=900-17°51/04"(+)=72    08  56    =codecl. 
900-/}=90°-32°57/55"       =57    02  05   =coalt. 

2  £=181°  53'  31" 


£=  90°  56'  45" 
coded.  =90° -5=  72    08  56 


S-  coded.  =  18° 

log  sin  S                   — 
"  sin  (S-  coded.  )  = 

"   sin  colat.            =9.900674 
"   sin  coalt,            =9.923762 

47/  49// 
9.  999941 
9.  508146 

9.  508087 

9. 824436  9.  824436 


<   cos2JJ.  =  9.683651 

«   cos  Lf  =  9.841825 

\A  =  45°  59X  35" 

^l=True  bearing  of  sun  =N.  91°  59X  10"  E. 

Angle  from  sun  to  flag  =(  — )  2    00  30 

True  bearing  of  flag  =N.  89°  58X  40"  E. 


INSTRUMENTS  AND  METHODS.  109 

The  above  equation  is  as  good  as  any  for  the  reduction  of  one  obser- 
vation, but  the  reduction  becomes  laborious  for  a  series  of  three 
observations. 

110.  The  third  of  the  above  series  is  also  selected  for  an  example 
of  reduction  by  the  equation: 


Tan  *  A  =    /CQS  4  (f +4>+S)  sin  4  (r+<ft-5) 
V  cos  4  (r- 0-«)  sin  4  (r-^+5) 

fc=  32°  57'  55" 

f  =  57°  02'  05"  r=57°  02'  05" 

0=  37    17  30  0=37    17  30 


94°  197  35"  £-0=19°  44'  35" 

5=  17    51  04  (+)  5=17    51  04  (+) 


$•+0+5=112°  1(X  39"  £-0+5=37°  35X  39X 

:  56°05/20//  J(r-^+5)=l! 


^=  94°  19X  35"  f — 0=19°  44X  35" 

5=  17    51  04  (+)  5=17    51  04  (+) 

-5=  76°  28X  31"  f -0-5=  1°  53X  31" 

_5)=  38°  14X  15"  i(r— 0— 5)=  0°  56r  45" 


log  cos  4(f +0+5)=  9.  746561 

"  sin  i(f+<^>— 5)=  9.  791636 


9. 538197 

cos  4(f-0-5)=9.  999941 
sin  i-(f-0+5)=9.  508152 


9.  508093    9.  50809$ 


log  tan2  4^4=        0.030104 
"   tan    ±A=        0.015052 


\A=      45°  59X  34" 

True  bearing  of  sun     =N.  91°  W  08"  E. 
Angle  from  sun  to  nag=(-)2    00  30 

True  bearing  of  flag     =N.  89°  58X  38"  E. 


110  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

111.  The  above  equation  is  as  good  as  any  for  the  reduction  of  one 
observation,  but  the  reduction  becomes  laborious  for  a  series  of  three 
observations.  However,  the  advantage  in  using  the  above  equation 
is  found  when  it  becomes  desirable  to  reduce  the  observations  for 
both  time  and  azimuth. 

Let  it  be  required  to  reduce  the  third  observation  of  the  above 
series  for  time,  making  the  reduction  by  the  following  equation: 


/    /* 

<=Vc 


cos  *(r+<H-5)  cos  *«•-*-« 

log  sin  i(r-f  0-5)=  9.  791636 

"   sin  }($•-*+ 5)=  9.508152 

9. 299788 

"   cos  i(r +0+5)  =9.  746561 
"   cos  i(r-4>-5)=9.  999941 


9. 746502    9. 746502 


tan 2  i  t  =  9. 553286 

tan    4  f  =  9. 776643 

i*  =30°52/34//    = 

*  =61°  45'  08//=4h  07m  01s 


Apparent  time  of  observation     =7h  52m  59s  a.  m. 
Equation  of  time  =    +6    05 

Local  mean  time  of  observation =7h  59m  04s  a.  m. 
Watch  time  of  observation          =7   52    54 


Watch  slow  of  1.  m.  t.  =       6m  10s 

112.  Example  of  direct  altitude  observation  of  the  sun  for  azimuth, 
eun  south  declination : 

Final  field  notes . 

March  18,  1910,  at  a  transit  point  in  Washington,  D .  C.,  in  latitude 
38°  53r  40"  N.,  and  longitude  77°  01'.6  W.,  at3h42m  p.  m.,  app.  t.,  I 
make  a  series  of  three  altitude  observations  upon  the  sun  for  azimuth, 
each  with  the  telescope  in  direct  and  reversed  positions,  observing 
opposite  limbs  of  the  sun,  and  reading  the  horizontal  deflection 
angle  from  a  flag  pole  about  20  chs.  to  the  S.,  SW.  to  the  sun: 


INSTRUMENTS  AND  METHODS. 


Ill 


Obser- 
vation. 

Telescope. 

Sun. 

Watch 
time. 

Vertical 
angle. 

—  9  

Horizontal  angle  flag 
to  sun. 

1st  

Direct  

q- 

3h  56°»  58>» 

25°  20' 

65°  00'         to  SW. 

Reversed  

-b 

3    58    48 

25   31 

64    45           "    " 

Mean 

3h  sym  533 

25°  25'  30" 

64°  52'  30"  "    " 

2nd.  .  . 

Direct..    .. 

q_ 

4h  Olm  48s 

24°  28' 

65°  56'          "    " 

Reversed.... 

1 

-b 

4   03    10 

24   44 

65   36           "    " 

Mean  . 

24°  36'  00" 

65°  46'  00"  "    " 

. 

3rd  

Direct  

9- 

4h  Q&*  58s 

23°  44' 

66°  44'           "    " 

« 

Reversed  

43 

4    07    30 

23    57 

66   26           "    " 

Mean  . 

23°  50'  30" 

66°  35'  00"  "    " 

By  1st  obsn.  flag  bears  S.  1°  0(K  02"  W. 
"  2nd  "  "  "  S.  1  00  20  W. 
"  3rd  "  "  "  S.  0  59  50  W. 


Mean  true  bearing  of  flag=S.  1°  00'  04"  W. 


Field  record. 

The  declination  of  the  sun  for  the  mean  period  of  the  three  obser- 
vations=l°  02X  16X/  S. 

The  following  reductions  are  made  to  obtain  the  true  vertical 
angles  of  the  above  observations: 

1st  obsn.         2nd  obsn.         3rd  obsn. 
v=2b°  25X  30"    24°  36X  00"    23°  5(K  30" 
Refraction=       -2    00  -2    06  *-2    10 

Parallax  =       +08  +08  +08 


=25°  23X  38"    24° 


02"     23° 


28A 


112  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

113.  The*  first  of  the  above  series  is  selected  for  an  example  of 
reduction  by  the  equation : 


Tan  \A= 
h=  25°  23'  38" 

$•=  64°  36X  22"  r=64°  36'  22' 

0=  38  53  40  0=38  53  40 


=103°  30'  02"  f-0=25°  42'  42" 

i=  1  02  16  (-)  '         5=  1  02  16  (-) 


=102°  27'  46"  £— 0+6=24°  40'  26" 

=  51°  13'  53"  4(f-0+5)=12°  20'  13A 


103°  30X  02"  f— 0=25°  42X  42" 

5=     1     02    16   (-)  5=  1     02    16   (-) 


-5=104°  32X  18"  ^-0-5=26°  44X  58A 

5 ;\  f\O®    ~\  f\/   nQ-'/  iff"      A*.       f\\ 1 QO    OQ^    *?Q^< 

— o)==  tjZi     _LO    uy  2\ i  ~~fy "~"O j ^^ J-O     ^.z    ^y 


log  cos  i(r+0+5)=  9. 796697 

5)=  9.898118 


9. 694815 

"  cos  J(r-0-5)=9.  988058 
"  'sin  i(f-0+5)=9. 329724 


9.317782    9.317782 


log  tan2  i  A    =      0. 377033 
"  tan  4  4    =      0.188516 


J  A          =57°  03X  44" 
bearing  of  sun=N.  114°  07X  28X/  W. 
Angle  from  sun  to  flag=  (+)64    52   30 


True  bearing  of  flag=N.  178°  59X  58/x  W. 
=S.       1°  00X  02"  W. 


INSTRUMENTS  AND  METHODS. 


1  13 


114.  Let  it  also  be  required  to  reduce  the  first  observation  of  the 
above  series  for  time,  making  the  reduction  by  the  following  equa- 
tion: 


i  / 


/si 
V  co 


cos 

log  sin  J(M-<£-5)= 
"   sin  l(r-0+5)= 


cosJ(M-0+«)= 
cos  i(r-4>-5)= 


cos  i(f-0-6) 
9.  898118 
9.  329724 

9.  227842 
9.796697 
9.988058 
9.  784755   9.  784755 


log  tan  2J  t=  9.443087 

"  tan    i  «=  9.721544 

i  £=27°  46'  29"      = 
£=55°  32'  58"=3h  42m  12s 
Apparent  time  of  obsn.     =3h  42m  12s  p.  m. 
Equation  of  time  =    +8     17 

Local  mean  time  of  obsn.=3h  50m  29s  p.  m. 
Watch  time  of  obsn.          =3    57     53 
Watch  fast  of  1.  m.  t.        =       7m  24s 

75th  meridian  time  of  comparison  with  a  Western 

Union  telegraph  clock        =4h  30m  00s  p.  m. 
Correction  for  longitude     =  —08    06 
L.  M.  T.  of  comparison 


4   21 

Watch  time  of  comparison  =4   29 
Watch  fast  of  1.  m.  t 


54 

20 


=        7m  269 


115.  The  second  observation  of  the  above  series  is  selected  for  an 
example  of  reduction  by  the  equation  : 
sin  5 


Cos  A— 


log  cos  $=9.  891149 

•"   cos  A=9.  958790 

9&9939 


—       -  r 
cos  <j>  cos  h 

log  sin  5=8.  257958 


—  tan  </>  tan  h 

(  -) 


log  tan  0=9.  906733 
"   tan  h  =9.  660053 


log 
nat(-) 


9.J849939 

8.408019 

.02559 


log 

nat(-) 
(-) 

cos.4=(-) 
66°  46X  20"  W. 


9.566786 
.36880 
.  02559 
.39439 


^=True  bearing  of  sun     =S. 

Angle  from  sun  to  flag=(-)65    46  00 
True  bearing  of  flag     =S.      1°  00X  20/ 


W. 


114  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

116.  The  third  observation  of  the  above  series  is  selected  for  an 
example  of  reduction  by  the  equation: 


Cos  J  A=  sn  (S- 


sin  colat.  sin  coalt. 

90°-4>=90°-38°  53'  40"   =  51°  06'  20"=colat. 
90°-5=90°-  1  02  16  (-)  =  91  02  16  =codecl. 
90°  -fc=90°  -23  48  28    =  66  11  32  =coalt. 


2  S=208°  20'  08" 

S=104°  10'  04A 
coded.  =90°  -5  =  91    02   16 


S-codecl.=  13°  07' 48" 
log  sin  S  =9. 986585 

"  sin  (S-codecl.)     =  9.356334 

9.342919 

"  sin  colat  =9.891149 

<c  sin  coalt.  =9.961376 


9.852525  9.852525 


log  cos2  \A  =  9. 490394 

"   cos  \A=  9.745197 

\A  =  56°  12X  35" 

4=True  bearing  of  sun      =  N.  112°  25X  10"  W. 

Angle  from  sun  to  flag  =  (+)  66    35  00 

True  bearing  of  flag      =  N.  179°  00X 10"  W. 

=  S.     0°  59X  50"  W. 


EQUAL  ALTITUDE   OBSERVATIONS   OP  THE   SUN   FOR   MERIDIAN. 

117.  The  true  meridian  may  be  established  by  the  method  of 
equal  altitude  observations  of  the  sun.  The  observation  is  not  wel  1 
adapted  to  line  work,  but  it  possesses  a  certain  usefulness  in  camp, 
in  that  the  surveyor  may  thus  determine  the  true  meridian  by  the 
sun  with  mere  approximations  as  to  time  and  latitude. 

The  fixation  of  the  true  meridian  by  this  method  depends  upon 
the  theory  that  the  sun's  center  at  equal  altitudes  occupies  sym- 
metrical positions  in  azimuth  east  and  west  of  the  meridian  in 
the  morning  and  in  the  afternoon  except  for  the  correction  neces- 


INSTRUMENTS  AND  METHODS.  115 

sary  to  be  applied  due  to  the  change  in  the  sun's  declination  in 
the  interval  between  the  a.  m.  and  p.  m.  observations: 

"dAd  "  :  Correction  in  azimuth  in  minutes  of  angular  measure  to  be 
applied  to  the  mean  position  in  azimuth  to  obtain  the  true  south 
point;  the  correction  is  to  be  applied  to  the  east  with  a  northerly 
hourly  change  in  declination,  or  to  the  west  with  a  southerly  hourly 
change. 

"d5  ":  Change  in  declination  of  the  sun  from  the  a.  m.  to  the  p.  m. 
observation,  expressed  in  minutes  of  angular  measure. 

"(£i+£2)":  The  sum  of  the  hour  angles  from  apparent  noon,  or  the 
total  watch  time  from  the  a.  m.  to  the  p.  m.  observation,  expressed 
in  angular  measure. 

A  A  _ 

>~ 


The  symmetry  of  the  equal  altitude  observation  is  maintained 
by  observing  opposite  limbs  in  azimuth  in  the  a.  m.  and  p.  m. 
observations,  in  connection  with  the  same  limb  in  vertical  angle 
in  both  observations. 

With  "%d5"  and  "ife+<a)"  calculated,  the  computation  can  be 
concluded  by  applying  to  "  %dd  "  the  declination  coefficient  obtained 
by  entering  Table  22  of  the  Standard  Field  Tables,  which  gives 
coefficients  for  computing  errors  in  azimuth  due  to  small  errors  in 
declination,  arguments:  "<£"  and  "K*i+*2)-" 

118.  An  equal  altitude  observation  of  the  sun  for  azimuth  consists 
in  reading  the  horizontal  deflection  angles  from  a  fixed  reference 
point  to  opposite  right  or  left  limbs  of  the  sun  in  a.  m.  and  p.  m. 
observations  simultaneously  with  the  same  upper  or  lower  limb 
at  the  epoch  of  equal  vertical  angle  in  both  observations,  from  the 
record  of  which  a  calculation  is  made  of  the  bearing  of  the  reference 
point  as  referred  to  the  true  meridian.     To  guard'against  error  the 
surveyor  is  required  to  make  a  series  of  three  equal  altitude  obser- 
vations, taking  the  resulting  mean.     The  most  suitable  a.  m.  and 
p.  m.  hours  for  this  observation  obtain  when  the  sun  is  moving 
rapidly  in  altitude  as  compared  with  a  relatively  small  change  in 
azimuth. 

EQUAL  ALTITUDE  OBSERVATIONS  OF  THE  SUN,  OBSERVING  PROGRAM. 

119.  Select  the  observing  station,  or  transit  point,  and  a  reference 
point  preferably  to  the  south,  and  not  nearer  than  5  or  10  chains 
distant. 


116  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

Thoroughly  level  the  transit  for  the  a.  m.  observation. 

Observe  and  record  the  horizontal  deflection  angle  from  the  fixed 
reference  point  to  the  sun's  right  limb,  and  the  vertical  angle  to  the 
sun's  lower  limb;  these  observations  must  be  simultaneous,  at  the 
epoch  of  which  the  sun  will  appear  as  indicated;  note  the  watch 

time  at  the  epoch  of  the  observation:  ^\- 
Thoroughly  level  the  transit  for  the  p.  m.  observation. 
With  the  same  vertical  angle  set  off  for  the  p.  m.  observation  follow 
the  sun's  left  limb  until  the  sun's  lower  limb  becomes  tangent,  as 
indicated,  recording  the  watch  time  and  horizontal  deflection  angle 

from  the  reference  point:  -p 

The  above  program  constitutes  one  observation.  A  series  of  three 
observations  are  taken  by  three  successive  a.  m.  settings  at  intervals 
of  about  four  or  five  minutes  of  time.  In  the  p.  m.  the  settings  are 
of  course  made  in  the  inverse  order. 

Consider  each  equal  altitude  observation  separately  and  subtract 
the  lesser  horizontal  angle  from  the  greater  and  divide  by  two. 

The  mean  of  the  three  half-differences  is  then  taken  to  determine 
the  horizontal  angle  from  the  reference  point  to  an  uncorrected  south 
point,  this  angle  to  be  applied  in  a  direction  to  equalize  the  south 
point  between  the  two  observed  positions  of  the  sun. 

Compute  the  differential  azimuth  correction  due  to  the  change  in 
the  sun's  declination  from  the  mean  period  of  the  a.  m.  to  the  mean 
period  of  the  p.  m.  observations,  and  apply  this  angle  to  the  mean 
of  the  half-differences  as  stated  above;  the  differential  azimuth  cor- 
rection is  to  be  applied  to  the  east  when  the  hourly  change  in  the 
sun's  declination  is  northerly  or  to  the  west  when  the  hourly  change 
in  the  sun's  declination  is  southerly;  the  computed  resultant  angle 
indicates  the  bearing  of  the  reference  point  referred  to  the  true 
meridian. 

The  correct  apparent  times  of  the  observations  do  not  need  to  be 
known,  as  the  function  "$(^+^2) "  equals  one-half  the  time  in  hours 
and  minutes,  by  the  surveyor's  watch,  from  the  a.  m.  to  the  p.  m. 
observation. 

The  equal  altitude  observation  may  be  modified  by  taking  a  p.  m. 
observation  one  day  followed  by  an  a.  m.  observation  the  next,  in 
which  case  the  functions  "%d8"  and  "  J(*i+^) "  are  to  be  computed 
for  the  period  from  the  p.  m.  to  the  a.  m.  observation;  and  the  differ- 


INSTRUMENTS  AND  METHODS. 


117 


ential  azimuth  correction,  "d  A&" ,  is  then  applied  in  the  opposite 
direction. 

120.  Example  of  equal  altitude  observation  of  the  sun  for  azimuth: 

Final  field  notes . 

May  3, 1913,  at  a  transit  point  in  Washington,  D.  C.,  in  latitude  38° 
53'  40"  N.,  and  longitude  77°  1'.6  W.,  at  9h27m  a.  m.  and  2h33m  p.  m., 
app.  t.,  I  make  a  series  of  three  equal  altitude  observations  upon  the 
sun  for  azimuth,  reading  the  horizontal  deflection  angle  from  a  flag- 
pole about  20  chs.  to  the  S.,  SE.  in  the  a.  m.  to  the  sun's  right  limb, 
and  SW.  in  the  p.  m.  to  the  sun's  left  limb;  equal  vertical  angles 
being  taken  to  the  sun's  lower  limb. 


Observation. 

Sun. 

Watch 
time. 

Vertical 
angle. 

Horizontal  angle  flag 
to  sun. 

1st  a  in 

Cj 

9h29m25s 

4S°28'00" 

67°20'00"            to  SE. 

3d  p  m 

•-P 

2  41   40 

65  28  30               to  SW. 

2d  a.  m 

q_ 

9h32mnOs 

49°05'00" 

1°51'30"  (DifF.) 
66°29'30"            to  SE' 

2d  p.  m      

i 
-P 

2  38   15 

64  38  00               to  SW. 

i 

5hOom25* 

2h32m49s 

1°51'30"  (DifT  ) 

3d  a.  m         

®r 

9h36m3Qs 

49°43'00" 

65°34'30"            to  SE. 

1st  p.ra  

_p 

2  34   45 

63  45  30               to  SW. 

i 

1°49W  (Diff.) 

One-half  differences,  or  bearing  angles  from  uncorrected  south 
point  to  flag: 

By  1st  obsn.=S.  0°  55'  45"  W. 
11  2d  "  =S.  0  55  45  W. 
"  3d  "  =S.  0  54  30  W. 


Mean  =S.  0°  55/  20"  W. 

Differential  azimuth  correction=    (+)  3X  53" 


Mean  true  bearing  of  flag 


=S.  0°  59X  13"  W. 


118 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


Field  record. 
The  hourly  change  in  the  sun's  declination  =44".  3  N. 


Hor.  ang.  a.  m.=J.  a.  m.-{-x=A-\-x 

Hor.  ang.  p.  m.=A  p.  m.—  x=AJr2dAd—  x 

Hor.  ang.  a.  m.—  Hor.  ang.  p.  m.—2x—2dA& 

Hor.  ang.  a.  m.—  hor.  ang.  p.  m. 

2—  _  -  -  --{-dAs 

The  following  computation  is  made  to  obtain  the  differential 
azimuth  correction  for  the  ahove  series: 

£  dS=JX5.08X44.3=112//;  log  Jd$=2.049218 
0=38°  53'  40"  N.  ;  log  cos  <f>       =9.891149 


=38°  10'  30" 
log  sin  J(<i+<2> 


9.791034 


9.682183 


9.682183 


log  d  ^5=2.367035 

d  As= Differential  azimuth  correction  =    233" 

=3X  53" 


INSTRUMENTS  AND  METHODS. 


119 


121.  The  following  reduction  to  obtain  the  value  of  the  differ- 
ential azimuth  correction  for  the  above  series  is  made  with  the  use 
of  Table  22  of  the  Standard  Field  Tables: 


K*i+^)i  or  hours  from  noon. 

2h 

2*33m 

3k 

35°  00' 

2.44 

2.05 

1.73 

38   54 

2.16 

40   00 

2.61 

2.19 

1.85 

Declination  coefficient  =2.16 

d  ^U=2.16Xi  </5=2.16X112"  =242" 

d  Ad=  differential  azimuth  correction  =4/  02" 

The  small  difference  (09")  in  the  computation  of  ltd  As"  in  the 
two  processes  of  reduction  is  due  to  the  error  in  adopting  a  coefficient 
obtained  by  linear  interpolation  in  Table  22  of  the  Standard  Field 
Tables,  the  tabular  interval  of  which  is  large.  Ordinarily  the  equal 
altitude  method  would  be  used  when  the  latitude  of  the  station  is 
uncertain,  and  the  slight  error  in  using  the  declination  coefficient 
taken  by  linear  interpolation  from  Table  22  is  small  enough  to  be 
negligible. 

122.  The  second  a.  m.  and  p.  m.  observations  of  the  above  series 
are  selected  for  an  example  of  reduction  to  the  sun's  center  and 
direct  computation  of  the  sun's  azimuth,  and  true  bearing  of  the 
flag,  by  the  equation: 


Cos  ^= 


tan  h 


Vertical  angle  to  sun's  lower  limb  =49°  05'  00" 
Reduction  to  sun's  center  =  +    15'  54" 

Refraction  49" 

Parallax  =+          06" 


Sun's  center,  h 


=49°  20'  11' 


120  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

Declination  of  the  sun  at  Greenwich  apparent  noon  =15°  34'  37"  N. 
Diff .  in  time  to  a.  m.  obsn. : 

For  longitude     =    5h08m 

For  time,  a.  m.  =  -2  33 


2.58 h  =    2h35m 

Diff.  in  declination  to  app.  t.  of  a.  m.  obsn.: 

2.58X44//.3=114//  =          V  54"  N . 


Sun's  decl.  a.  m.  obsn.  =  15°  36'  31"  N. 

Diff  .to  p.m.obsn., already  computed(2XH2"=224")=         3'  44"  N . 

Sun's  decl.  p.  m.  obsn.  =  15°  4(X  15"  N. 

a.  m.  obsn.  p.  m.  obsn. 

log  cos  0=9.  891149    log  sin  5=9.  429856(-f)  log  sin  5=9.  431541(+) 
"    cos  A=9.  813992 


9. 705141  9. 705141  9. 705141 


"tan<£    =9.906733  log  9.724715  log           9.726400 

"tan  ft     =0.065991  nat(+)      -53054  nat  (+)    .53260 

log  9.972724 

nat(-)     .93913  (-)      .93913  (-)    .93913 


cosJ.    =  (-)      .40859  (-)    .40653 

.  ' 

^=true  bearing  of  sun    =S.  65°  53X  02"  E.  S.  66°  OCX  47"  W. 

Horizontal    angle    from 
flag  to  sun's  right  and 

left  limbs  =     66°  297  30"  to  SE.    64°  38X  00"  to  SW. 

Reduction  to  sun's  cen- 

15^ 

ter=  -  =   (+)  24X24"  (+)  24X  24" 

cos  49°  2(K  - 


Hor.  ang.  to  sun's  center  =     66°  53r  54"  to  SE.    65°  02X  24"  to  SW. 
Sun's  azimuth  as  com- 
puted above  =S.  65°  53r  02"  E.     S.  66°  0(X  47"  W. 

True  bearing  of  flag          =S.    100(K52"W.     S.    0°  58X  23"  W. 
Mean  true  bearing  of  flag  =S.    0°  59X  37"  W. 

•The  discrepancy  between  the  a.  m.  and  p.  m.  results  suggests  a 
systematic  instrumental  error  ordinarily  eliminated  by  taking  direct 


INSTRUMENTS  AND  METHODS.  121 

and  reversed  observations,  which  in  this  instance  is  of  opposite  effect 
in  a.  m.  and  p.  m.  hours  and  apparently  eliminated  in  the  mean 
result. 

123.  One  additional  fact  should  be  noted  relative  to  the  several 
reductions  of  the  above  equal  altitude  observations: 

By  above  direct  computation,  A  p.  m.  =66°  0(X  47" 

A  a.  m.  =65°  53'  02" 


Difference =2dAs  =        7'  45" 
dAs  =        3X  53" 


This  value  for  dA8  (3'  53")  agrees  with  same  function  as  first 
.computed. 

124.  Upon  concluding  the  subject  of  azimuth  determinations  it 
will  be  of  interest  to  note  that  the  weighted  mean  of  a  large  number 
of  observations  gives  a  value  of  S.  0°  59'  25"  W.  for  the  azimuth  of 
the  line  from  the  Washington,  D .  C.,  transit  point  to  the  flag  pole  here- 
tofore described.  A  comparison  of  the  methods  and  results  of  the  va- 
rious observations  as  given  on  the  preceding  pages  suggests  that  the 
surveyor  should  seldom  be  without  means  by  which  accurately  to 
determine  time,  latitude  and  azimuth  at  any  place  in  the  field, 
however  remote,  and  should  doubt  arise  as  to  his  results  a  " check" 
by  independent  method  is  nearly  always  available  and  a  certain 
guide  as  to  the  accuracy  of  the  determinations.  It  might  be  added 
that  a  careful  surveyor  will  not  fail  to  surround  his  methods  with 
adequate  verification  to  insure  the  accuracy  required  in  the  execution 
of  the  public-land  surveys. 

THE   TRUE   PARALLEL  OF  LATITUDE. 

125.  The  base  lines  and  standard  parallels  of  the  rectangular 
system  are  established  on  the  true  parallel  of  latitude ;  the  random 
latitudinal  township  boundary  lines  are  also  projected  on  the  same 
curve;  this  curve  is  defined  by  a  plane  at  right  angles  to  the  earth's 
polar  axis  cutting  the  earth's  surface  on  a  small  circle.  At  every 
point  on  the  true  parallel  the  curve  bears  due  east  and  west,  the 
direction  of  the  line  being  at  right  angles  to  the  meridian  at  every 
point  along  the  line.  Two  points  at  a  distance  of  20  chains  apart  on 
the  same  parallel  of  latitude  may  be  said  to  define  the  direction  of 
the  curve  at  either  point,  without  appreciable  error,  but  the  projec- 
tion of  a  line  so  defined  in  either  direction,  easterly  or  westerly, 
55465  ° — 19 — T-9 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 

would  describe  a  great  circle  of  the  earth  gradually  departing  south- 
erly from  the  true  parallel.  The  great  circle  tangent  to  the  parallel 
at  any  origin  or  reference  point  along  the  parallel  is  known  as  the 
"  tangent  to  the  parallel* "  and  it  is  coincident  with  the  true  latitude 
curve  only  at  the  point  of  origin.  The  rate  of  the  change  of  the 
azimuth  of  the  tangent  is  a  function  of  the  latitude  on  the  earth's 
surface.  The  azimuth  of  the  tangent  varies  directly  as  the  distance 
from  the  origin,  and  the  offset  distance  from  the  tangent  to  the 
parallel  varies  as  the  square  of  the  distance  from  the  point  of  tan- 
gency.  A  great  circle  connecting  two  distant  points  on  the  same 
latitude  curve  has  the  same  angle  with  the  meridian  at  both  points 
and  the  azimuth  of  such  a  line  at  the  two  points  of  intersection  is  a 
function  of  one-half  the  distance  between  the  points.  * 

There  are  three  general  methods  of  establishing  a  true  parallel  of 
latitude  which  may  be  employed  independently  to  arrive  at  the 
same  result:  (1)  The  solar  method;  (2)  the  tangent  method;  and, 
(3)  the  secant  method. 

SOLAR    METHOD. 

126.  The  solar  instruments  are  capable  of  following  the  true 
parallel  of  latitude  without  substantial  offsets.  If  such  an  instru- 
ment, in  good  adjustment,  is  employed,  the  true  meridian  may  be 
determined  by  observation  with  the  solar  at  each  transit  point.  A 
turn  of  90°  in  either  direction  then  defines  the  true  parallel,  and  if 
sights  are  taken  not  longer  than  from  20  to  40  chains  distant,  the  line 
so  established  does  not  appreciably  differ  from  the  theoretical 
parallel  of  latitude.  The  locus  of  the  resulting  line  is  a  succession 
of  points  each  one  at  right  angles  to  the  true  meridian  at  the  pre- 
vious station.  However,  during  a  period  each  day  the  solar  is  not 
available,  and  during  this  time,  also  whenever  the  sun  may  be 
obscured  by  clouds,  or  on  account  of  a  disturbance  of  the  adjust- 
ments of  the  solar  attachment,  and  whenever  an  instrument  without 
solar  attachment  is  employed,  reference  must  be  made  to  a  transit 
line  from  which  to  establish  the  true  latitude  curve  by  one  of  the 
following  methods. 

TANGENT   METHOD. 

127.  The  tangent  method  of  determination  of  the  true  latitude 
curve  consists  in  establishing  the  true  meridian  at  the  point  of 
beginning,  from  which  a  horizontal  deflection  angle  of  90°  is  turned 
to  the  east  or  west,  as  may  be  required,  and  the  projection  of  the  line 
thus  determined  is  called  the  tangent.  The  tangent  is  projected  6 


INSTRUMENTS  AND  METHODS. 


123; 


..,-r;F  / 


-~-4g 


,. 


/¥  / 


124  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

miles  in  a  straight  line,  and  as  the  measurements  are  completed  for 
each  corner  point,  proper  offsets  are  measured  north  from  the  tangent 
to  the  parallel,  upon  which  line  the  corners  are  established. 

In  Table  12,  Standard  Field  Tables,  are  given  the  bearing  angles 
or  azimuths  of  the  tangent  to  the  parallel,  referred  to  the  true  S. 
point,  tabulated  for  any  degree  of  latitude  from  25°  to  70°  N.,  for  the 
end  of  each  mile  from  1  to  6  miles.  At  the  point  of  beginning  the 
tangent  bears  east  or  west,  but  as  the  projection  of  the  tangent  is 
continued  the  deviation  to  the  south  increases  in  accordance  with 
rules  already  stated. 

In  Table  13,  Standard  Field  Tables,  are  shown  the  various  offsets 
from  the  tangent  north  to  the  parallel,  tabulated  for  any  degree  of 
latitude  from  25°  to  70°  N.,  for  each  half  mile  from  J  to  6  miles. 

The  accompanying  diagram  illustrates  the  establishment  of  a 
standard  parallel  in  latitude  45°  34'.  5  N.,  by  the  tangent  method. 
(See  Fig.  14 . )  The  form  of  record  is  shown  in  the  specimen  field  notes . 

Objection  to  the  use  of  the  tangent  method  in  a  timbered  country 
is  found  owing  to  the  requirement  that  all  blazing  is  to  be  made  on 
the  true  surveyed  lines.  Also,  all  measurements  to  items  of  topog- 
raphy entered  in  the  field  notes  are  to  be  referred  to  the  true  estab- 
lished liifes.  These  objections  to  the  tangent  method,  on  account  of 
the  increasing  distance  from  the  tangent  to  the  parallel,  are  largely 
removed  in  the  secant  method. 

SECANT    METHOD. 

128.  The  designated  secant  is  a  great  circle  which  cuts  any  true 
parallel  of  latitude  at  the  first  and  fifth  mile  corners,  and  is  tangent  to 
an  imaginary  latitude  curve  at  the  third  mile  point.  From  the 
point  of  beginning  to  the  third  mile  corner  the  secant  has  a  north- 
easterly or  northwesterly  bearing;  at  the  third  mile  corner  the  secant 
bears  east  or  west;  and  from  the  third  to  the  sixth  mile  corners  the 
secant  has  a  southeasterly  or  southwesterly  bearing,  respectively, 
depending  upon  the  direction  of  projection,  east  or  west.  From  the 
point  of  beginning  to  the  first  mile  corner  and  from  the  fifth  to  the 
sixth  mile  corners  the  secant  lies  south  of  the  true  parallel,  and  from 
the  first  to  the  fifth  mile  corners  the  secant  lies  north  of  the  true 
parallel.  It  will  thus  be  seen  that  the  secant  method  is  a  mere 
modification  of  the  tangent  method,  so  arranged  that  the  minimum 
offsets  can  be  made  from  the  projected  transit  line  to  the  established 
true  parallel  of  latitude. 


INSTRUMENTS  AND  METHODS. 


125 


126  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

The  secant  method  of  determination  of  the  true  latitude  curve  con- 
sists in  establishing  the  true  meridian  at  a  point  south  of  the  begin- 
ning corner  a  measured  distance  taken  from  the  table,  from  which 
meridian  the  proper  horizontal  deflection  angle,  as  taken  from  the 
table,  is  turned  to  the  northeast  or  northwest  to  define  the  secant. 
The  secant  is  projected  6  miles  in  a  straight  line,  and  as  the  measure- 
ments are  completed  for  each  corner  point,  proper  offsets  are  meas- 
ured, north  or  south,  from  the  secant  to  the  parallel,  upon  which 
parallel  the  corners  are  established. 

In  Table  14,  Standard  Field  Tables,  are  given  the  bearing  angles  or 
azimuths  of  the  secant,  referred  to  the  true  N.  point  for  the  first  3 
miles,  and  the  same  symmetrical  bearing  angles  or  azimuths  referred 
to  the  true  S.  point  for  the  last  3  miles,  tabulated  for  any  degree  of 
latitude  from  25°  to  70°  N.,  for  the  end  of  each  mile  from  0  to  6 
miles. 

In  Table  15,  Standard  Field  Tables,  are  shown  the  various  offsets 
from  the  secant  to  the  parallel,  tabulated  for  any  degree  of  latitude 
from  25°  to  70°  N.,  for  each  half  mile  from  0  to  6  miles. 

The  accompanying  diagram  illustrates  the  establishment  of  a 
standard  parallel  in  latitude  45°  34'.5  N.  by  the  secant  method. 
(See  Fig.  15.)  The  form  of  record  is  shown  in  the  specimen  field  notes. 

The  secant  method  is  recommended  for  its  simplicity  of  execution 
and  proximity  to  the  true  latitude  curve,  as  all  measurements  and 
cutting  by  this  method  are  substantially  on  the  true  parallel. 

CONVERGENCY   OF  MERIDIANS. 

129.  The  linear  amount  of  the  convergency  of  two  meridians  is  a 
function  of  their  distance  apart,  of  the  length  of  the  meridian  between 
two  reference  parallels,  of  the  latitude,  and  of  the  spheroidal  form 
of  the  earth's  surface. 

The  following  equation  is  convenient  for  the  analytical  compu- 
tation of  the  linear  amount  of  the  convergency  on  the  parallel,  of 
two  meridians  any  distance  apart,  and  any  length.  The  correction 
for  convergency  in  any  closed  figure  is  proportional  to  the  area,  and 
may  be  computed  from  an  equivalent  rectangular  area: 
' ' m\  " :  Measurement  along  the  parallel. 
"  m#  " :  Measurement  along  the  meridian . 
"a":  Equatorial  radius  of  the  earth =3963.  3  miles. 


INSTRUMENTS  AND  METHODS. 


127 


"c?rax":  Linear  amount  of  the  convergency  on  the  parallel,  of  two 
meridians  distance  apart  "m\,"  and  length  "m<£"  along 
the  meridian:  "</m\",  "m\",  "m$"  and  "a"  to  be 
expressed  in  the  same  linear  unit: 


m\  m<}> 
=  tan 


Example  of  computation  of  the  convergency  of  two  meridians  24 
miles  long  and  24  miles  apart  in  a  mean  latitude  of  43°  2(X: 


nat  1 
log* 


1.  0000000 


sill  43°  20' 


nat 


log' 


=8.  915  2515 
=8.  915  2515 
=9.  836  477 
=9.  836  477 

=7.  503  457 


9.998  614 


0.  0031875 
0.  9968125 


T^2~sin2l>  =9.999  307 
tan  43°  207  =9.  974  720 


"      24    , 

u      a 

"      80* 

u  product 
."3963.3 


nat 


=1.  380  211 
=1.  380  211 
=1.  903  090 

=4.  637  539 
=3.  598  057 

=1.  039  482 
10. 9517      chs. 


The  convergency,  measured  on  the  parallel,  of  two  meridians  24 
miles  apart  and  24  miles  long,  in  a  mean  latitude  of  43°  207,  is  there- 
fore found  to  be  10.95  chains.  The  convergency  of  the  east  and  west 
boundaries  of  a  regular  township  in  the  same  latitude  would  be 
equal  to  one-sixteenth  of  the  convergency  of  the  east  and  west 
boundaries  of  the  quadrangle  as  computed  above,  or  68.44  links, 
which  agrees  with  the  value  taken  from  Table  11  of  the  Standard 
Field  Tables. 

*This  factor  is  introduced  here  for  the  purpose  of  conversion  from  the  unit  ex- 
pressed in  miles  to  the  unit  expressed  in  chains. 


128  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

130.  In  Table  11,  Standard  Field  Tables,  are  tabulated  the  linear 
amounts  of  the  convergency  of  meridians,  6  miles  long  and  6  miles 
apart,  for  each  degree  of  latitude  from  25°  to  70°  N.,  together  with 
the  angle  of  convergency  of  the  same  meridians.     These  amounts  of 
linear  convergency  are  at  once  the  proper  corrections  to  apply  to 
the  north  boundary  of  a  regular  township  in  the  computation  of  the 
closing  error  around  a  township,  or  other  computation  by  which  a 
theoretical  length  of  a  north  or  south  boundary  of  a  township  is  com- 
pared with  the  length  of  the  opposite  boundary;  the  tabulated  linear 
amounts  of  convergency  are  equal  to  double  the  amounts  of  the  offsets 
from  a  tangent  to  the  parallel  at  6  miles  for  the  same  latitudes. 
Simple  interpolation  may  be  made  for  any  intermediate  latitude, 
and  the  amount  of  the  convergency  for  a  fractional  township  or  other 
figure  may  be  taken  in  proportion  to  the  tabulated  convergency  as 
the  fractional  area  is  to  36  square  miles. 

The  tabulated  angle  of  convergency  represents  at  once  the  devia- 
tion in  azimuth  of  the  tangent  from  the  parallel  at  6  miles;  and  %, 
HJ  M>  %>  an(i  6/e  °f  the  tabulated  angles  of  convergency  represent 
at  once  the  amounts  of  the  correction  in  the  bearing  of  meridional 
section  lines  to  compensate  for  convergency  within  a  township. 

In  the  same  table  are  given  the  differences  of  longitude  for  6  miles 
in  both  angular  and  time  measure,  also  the  differences  of  latitude, 
for  1  or  6  miles,  in  angular  measure,  in  the  various  tabulated  latitudes. 

131.  In  the  plan  of  subdivision  of  townships  the  meridional  section 
lines  are  established  parallel  to  the  east  boundary  or  other  governing 
line;  this  necessitates  a  slight  correction  on  account  of  the  angular 
convergency  of  meridians.    Meridional  section  lines  west  of  the 
governing  line  are  deflected  to  the  left  of  the  bearing  of  the  governing 
line  the  amount  shown  in  the  second  part  of  Table  2,  Standard  Field 
Tables,  which  is  entered  under  two  arguments:  (1)  Latitude,  and  (2) 
distance  from  the  governing  line.    Meridional  section  lines  east  of  a 
governing  boundary  are  given  the  same  amount  of  correction  for 
bearing,  but  the  deflection  is  made  to  the  right. 

LENGTHS  OF  ARCS  OF  THE  EARTH'S  SURFACE. 

132.  All  computations  involving  a  difference  of  latitude  for  a 
given  measurement  along  a  meridian  or  the  converse  calculation,  or 
other  computations  involving  a  difference  of  longitude  for  a  given 
measurement  along  a  parallel  or  a  similar  converse  calculation,  are 
readily  accomplished  by  the  use  of  the  values  given  in  Table  16, 
Standard  Field  Tables;  this  table  gives  the  lengths  in  miles  and 


INSTRUMENTS  AND  METHODS.  129 

decimal  part  of  a  mile  of  one  degree  of  longitude  measured  on  the 
parallel,  and  the  lengths  in  miles  of  one  degree  of  latitude  measured 
on  the  meridian,  for  any  latitude  from  25°  to  70°  N. 

The  above  tabulated  values  may  be  reduced  to  miles  and  chains, 
or  to  chains  or  feet,  as  convenient.  In  taking  out  lengths  of  degrees 
of  longitude  measured  on  the  parallel  an  exact  linear  interpolation 
may  be  made,  and  in  taking  out  lengths  of  degrees  of  latitude  meas- 
ured on  the  meridian  the  value  should  be  taken  out  for  the  mean 
position  in  latitude  of  that  portion  of  the  meridian  whose  length  it 
is  desired  to  compute. 

133.  The  first  part  of  Table  2,  Standard  Field  Tables,  has  been 
arranged  for  the  reference  of  the  latitude  of  any  point  within  a  town- 
ship to  the  south  boundary,  the  only  argument  being  the  miles  and 
chains  distant  from  the  south  boundary.  Thus  with  the  use  of  this 
table  all  observations  for  latitude  within  a  township  may  be  reduced 
to  the  south  boundary;  and  conversely,  given  the  latitude  of  the 
south  boundary  of  a  township,  the  latitude  of  any  station  within  the 
township  may  readily  be  obtained  by  applying  the  difference  given 
in  the  table  for  the  known  distance  north. 


CHAPTER  III. 
SYSTEM  OF  RECTANGULAR  SURVEYS. 

GENERAL   SCHEME. 

134:.  In  the  preceding  chapters  there  has  been  outlined  the  sys- 
tem of  nomenclature  and  procedure  relating,  in  general  terms,  to  the 
survey  of  the  public  domain.  It  is  confidently  assumed  that  the 
United  States  surveyor  has  become  impressed  with  the  purpose  of 
his  task  and  the  stability  and  dignity  which  should  be  attached  to  a 
work  so  great  and  important,  commensurate  with  its  broad  founda- 
tion in  law  and  science. 

For  the  purpose  of  disposal  of  the  public  domain  the  law  provides, 
in  general  terms,  for  its  description,  subdivision  and  identification 
in  conformity  with  the  following  general  scheme: 

1st.  The  township,  6  miles  square,  containing  36  sections,  each  1 
mile  square. 

2d.  The  numbering  of  the  townships  meridionally  into  a  range  and 
latitudinally  into  a  tier,  from  which  the  necessity  at  once  appears 
for  the  selection  of  independent  initial  points,  each  to  serve  as  an 
origin  for  the  extension  of  surveys  synchronously  needed  in  somewhat 
widely  separated  localities,  to  provide  for  which,  principal  or  gov- 
erning meridians  and  base  lines  have  been  established,  to  which 
might  be  related  the  surveys  executed  in  each  of  such  localities. 

3d.  The  establishment  of  guide  meridians  and  correction  lines  or 
standard  parallels  at  intervals  sufficiently  near  each  other  to  main- 
tain a  practical  workable  adherence  to  the  legal  •definition  of  the 
primary  unit,  the  township  6  miles  square,  and  at  the  same  time  to 
reduce  to  a  minimum  the  number  of  corners  required. 

4th.  The  placing  of  fractional  sections  on  the  north  and  west  bound- 
aries of  the  township. 

5th.  The  subdivision  of  the  townships  into  36  sections  by  running 
parallel  lines  through  the  township  from  south  to  north  and  from 
east  to  west  at  distances  of  1  mile. 

6th .  The  inflexible  declaration  of  the  integrity  of  the  corners  marked 
in  the  public  surveys  as  the  proper  legal  corners  of  the  sections 
or  of  the  subdivisions  of  the  sections  which  they  were  intended  to 

131 


132  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

designate,  together  with  the  equally  important  provisions  (a)  that 
the  boundary  lines  actually  run  and  marked  shall  be  and  remain 
the  proper  boundary  lines  of  the  sections  or  subdivisions  for  which 
they  were  intended;  (6)  that  the  length  of  such  lines  as  returned 
by  the  surveyors  shall  be  held  as  the  true  length  thereof;  and  (c) 
that  the  sections  shall  be  subdivided  by  running  straight  lines 
from  the  established  quarter-section  corners  to  the  opposite  estab- 
lished quarter-section  corners. 

135.  The  townships  will  be  numbered  to  the  north  or  south  com- 
mencing with  number  1  at  the  base  line,  and  with  range  numbers  to 
the  east  or  west  beginning  with  number  1  at  the  principal  meridian. 

The  36  sections  into  which  a  township  is  subdivided  are  numbered 
commencing  with  number  1  in  the  northeast  section  of  the  township, 
proceeding  thence  west  to  section  6,  thence  south  to  section  7,  thence 
east  to  section  12,  and  so  on,  alternately,  to  number  36  in  the  south- 
east section.  In  the  case  of  fractional  townships,  the  sections  will 
bear  the  same  numbers  they  would  have  had  if  the  townships  were 
full,  that  is  to  say  the  section  numbers  should  be  employed  which 
are  the  proper  section  numbers  relating  to  the  sides  which  are  the 
governing  boundaries,  leaving  any  deficiency  to  fall  on  the  opposite 
sides. 

136.  The  specimen  field  notes  will  serve  to  illustrate  the  method 
of  running  lines  to  form  quadrangles  24  miles  square;  the  method 
of  running  the  exterior  lines  of  townships;  and  the  method  of  sub- 
dividing  regular   townships.     The    methods   here    presented    are 
designed  to  insure  a  full  compliance  with  every  practicable  require- 
ment, meaning  and  intent  of  the  surveying  laws. 

137.  By  the  terms  of  the  original  law  and  by  general  practice 
section  lines  are  surveyed  from  south  to  north  and  from  east  to  west, 
in  order  uniformly  to  place  excess  or  deficiency  of  measurement  on 
the  north  and  west  sides  of  the  townships.     For  convenience  the 
exterior  lines  on  which  subdivisions  are  based  are  called  the  govern- 
ing boundaries.     In  unusual  cases  the  north  and  west  boundaries 
may  be  employed  to  govern  the  subdivision  of  a  township,  and  in 
extreme  cases  an  irregular  township  may  be  without  even  a  single 
governing  boundary. 

INITIAL   POINTS. 

138.  Initial  points  from  which  the  lines  of  the  public  surveys  are 
to  be  extended  will  be  established  whenever  necessary,  under  such 
special  instructions  as  may  be  prescribed  in  each  case  by  the  Com- 


SYSTEM   OF   RECTANGULAR   SURVEYS.  133 

missioner  of  the  General  Land  Office.  The  initial  points  are  to  be 
selected  with  a  view  to  their  control  of  extensive  agricultural  areas 
within  reasonable  geographical  limitations.  Upon  the  establish- 
ment of  an  initial  point,  the  position  of  the  point  in  latitude  and  longi- 
tude is  to  be  determined  by  accurate  field  astronomical  methods. 

During  the  period  since  the  organization  of  the  system  of  rectan- 
gular surveys  numbered  and  locally  named  principal  meridians  and 
base  lines  have  been  established  as  shown  by  the  accompanying 
tabular  exhibit.  These  bases  and  meridians  may  be  found  by 
examining  the  large  wall  map  of  the  United  States  published  by  the 
General  Land  Office;  they  are  also  shown  upon  the  various  official 
State  maps,  and  upon  a  special  map  entitled ' '  United  States,  Showing 
Principal  Meridians,  Base  Lines  and  Areas  Governed  Thereby. " 

139.  The  latitudes  and  longitudes  given  in  the  following  table  are 
based  upon  the  best  obtainable  information,  but  in  some  cases  the 
values  shown  are  only  approximately  correct  owing  to  the  fact  that 
many  of  the  initial  points  were  fixed  in  position  and  the  surveys 
therefrom  largely  completed  before  the  same  importance  was  at- 
tached to  the  matter  of  accurate  latitudes  and  longitudes  as  at  the 
present  time.     It  may  also  be  noted,  by  way  of  explanation,  that 
present-day  facilities  for  accurate  field  astronomical  determinations 
were  not  available  to  the  early  surveyors.     It  is  not  expected  that 
the  values  of  the  latitudes  given  in  the  table  will  be  used  as  the 
basis  of  the  calculation  of  the  latitude  of  an  unknown  station,  in  lieu 
of  a  field  determination  thereof,  except  as  an  approximate  value 
may  satisfy  all  requirements.     The  coordinates  of  the  earliest  sur- 
veys in  Ohio  can  not  be  conveniently  tabulated,  but  they  are  shown 
upon  the  maps  as  stated  above. 

PRINCIPAL   MERIDIAN. 

• 

140.  This  line  shall  conform  to  the  true  meridian  and  will  be 
extended  from  the  initial  monument,  either  north  or  south,  or  in 
both  directions,   as  the  conditions  may  require;  regular  quarter- 
section  and  section  corners  will  be  established  alternately  at  inter- 
vals of  40  chains,  and  regular  township  corners  at  intervals  of  480 
chains;  meander  corners  will  be  established  at  the  intersection  of 
the  line  with  all  meanderable  bodies  of  water. 

141.  In  the  survey  of  the  principal  meridian  and  the  other 
standard  lines  (base  lines,  standard  parallels  and  guide  meridians), 
hereinafter  described,  two  independent  sets  of  measurements  will 


134 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


MERIDIANS  AND  BASE  LINES  OF  THE  UNITED  STATES  RECTANGULAR 

SURVEYS. 


Meridians. 

Governing  surveys  (wholly  or 
in  part)  in  States  of— 

Longitude 
of  principal 
meridians 
west  from 
Greenwich. 

Latitude 
of  base 
lines 
north  from 
Equator. 

BlackHills  

South  Dakota  

104    03    00 

44    00    00 

Boise 

Idaho 

116    24    15 

43    22    31 

Chickasaw  

Mississippi  

89    15    00 

34    59    00 

Choctaw 

.do 

90    14    45 

31    54    40 

Cimarron        

Oklahoma  

103    00    00 

36    30    00 

Copper  River 

Alaska 

145    18    42 

61    49    11 

Fairbanks  ..  

Alaska  

147    38    33 

64    51    49 

Fifth  Principal 

Arkansas,   Iowa,   Minnesota 

91    03     42 

34    44    00 

First  Principal  .   .        .  . 

Missouri,    North    Dakota^ 
and  South  Dakota. 
Ohio  . 

84    48    50 

41    00    00 

Fourth  Principal  

Illinois  

90    28    45 

40    00    30 

Do                        .  . 

Minnesota  and  Wisconsin 

90    28    45 

42    30    00 

Gila  and  Salt  River  

Arizona  

112    17    25 

33    22    40 

TTuTTibolflt 

California 

124    08    00 

40    25    12 

Huntsville 

Alabama 

86    34    45 

35    00    00 

Indian 

Oklahoma 

Q7    14    30 

34    30    00 

Louisiana  

Louisiana  

92    24    15 

31    00    00 

Michigan 

Michigan 

84    22    24 

42    26    30 

Mount  Diablo  

California  and  Nevada 

121    54    48 

37    51    30 

Navajo 

Arizona  and  New  Mexico 

108    32    45 

35    45    00 

New  Mexico  Principal  .  .  . 
Principal 

Colorado  and  New  Mexico  
Montana 

106    53    40 
111    38    50 

34    15    25 
45    46    48 

Salt  Lake                .  .  . 

Utah.... 

111    54    00 

40    46    04 

San  Bernardino 

California 

116    56    15 

34    07    10 

Second  Principal  ....  . 

Illinois  and  Indiana 

86    28    00 

38    28    20 

Seward 

Alaska 

149    21    53 

60    07    26 

Sixth  Principal  

Colorado,  Kansas,  Nebraska, 

97    23    00 

40    00    00 

St.  Helena  

South  Dakota,  and  Wyo- 
ming. 
Louisiana  

91    09    15 

31    00    00 

St.  Stephens 

Alabama  and  Mississippi.  . 

88    02    00 

31    00    00 

Tallahassee 

Florida 

84    16    42 

30    28    00 

Third  Principal  
Uintah 

Illinois  

Utah 

89    10    15 
109    57    30 

38    28    20 
40    26    20 

Ute 

Colorado          

108    33    20 

39    06    40 

Washington 

Mississippi 

91    09    15 

31    00    00 

Willamette 

Oregon  and  Washington 

122    44    20 

45    31    00 

Wind  River 

Wyoming 

108    48    40 

43    01    20 

SYSTEM   OF  RECTANGULAR   SURVEYS.  135 

be  employed,  unless  subdivisional  closings  thereon  are  provided  in 
the  same  assignment  with  the  standard  line,  in  which  case  the  clos- 
ings will  furnish  a  satisfactory  verification  of  the  length  of  the  lines 
thus  surveyed.  Where  such  closings  are  not  to  be  made  during  the 
progress  of  the  same  survey,  the  proper  supervising  officer  will  pro- 
vide suitable  instructions  for  the  employment  of  a  second  set  of 
chainmen,  or  for  the  duplication  of  the  measurement  by  the  one  set 
of  chainmen.  In  either  case,  where  two  independent  sets  of  measure- 
ments are  employed,  the  distance  to  the  mean  point,  and  the  differ- 
ence between  the  measurements  to  each  corner  established,  will  be 
shown  in  the  field  notes;  a  form  of  record  is  given  in  the  specimen 
field  notes. 

142.  Should  the  difference  between  the  two  sets  of  measurements 
of  any  standard  line,  as  above  provided,  exceed  20  links  per  80  chains, 
it  is  required  that  the  line  be  remeasured  to  reduce  the  difference, 
the  final  measurement  of  the  line  only  to  be  shown  in  the  field  notes. 
Should  the  successive  independent  tests  of  the  alinement  of  any 
standard  line,  or  the  average  tests  of  the  solar  attachment  employed 
in  the  projection  thereof,  indicate  that  the  line  has  deflected  from 
the  true  cardinal  course  to  exceed  3'  00//,  the  necessary  corrections 
will  be  made  to  reduce  the  deviation  in  azimuth,  the  field  notes  of 
the  true  line  only  being  shown.    Every  reasonable  effort  will  be 
exercised  to  insure  the  accuracy  of  both  the  alinement  and  the  meas- 
urement of  the  standard  lines,  and  the  stated  discrepancies  are  the 
maximum  that  will  be  allowed  in  new  surveys;  corrective  steps  will 
be  required  where  the  differences  are  beyond  the  maximum. 

BASE  LINE. 

143.  From  the  initial  monument  the  base  line  will  be  extended 
east  and  west  on  a  true  parallel  of  latitude;  upon  the* true  line  stand- 
ard quarter-section  and  section  corners  will  be  established  alter- 
nately at  intervals  of  40  chains,  and  standard  township  corners  at 
intervals  of  480  chains;  meander  corners  will  be  established  at  the 
intersection  of  the  line  with  all  meanderable  bodies  of  water. 

The  manner  of  making  the  measurement  of  the  base  line  and  the 
accuracy  of  both  the  alinement  and  measurement  will  be  the  same 
as  required  in  the  survey  of  the  principal  meridian.  Any  one  of  the 
methods  heretofore  set  forth  for  the  determination  of  the  alinement 
of  the  true  latitude  curve  may  be  used  as  existing  conditions  may 
require  and  the  detailed  process  will  be  fully  stated  in  the  field  notes. 


13(5 


MANUAL,  OF  SURVEYING  INSTRUCTIONS. 


STANDARD   PARALLELS. 

144:.  Standard  parallels,  which  are  also  called  correction  lines, 
are  extended  east  and  west  from  the  principal  meridian,  at  intervals 
of  24  miles  north  and  south  of  the  base  line,  in  the  manner  prescribed 
for  the  survey  of  the  base  line. 

Fi3.l6. 


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R.2E. 

R.3E. 

R4E 

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i 
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Stan 

dard 

Parallel       J 

>outh 

Illustrating  the  survey  of  quadrangles    each  embracing  16  townships  bounded 
by  standard  lines,  and  showing  the  coordinate  system  of  numbering  the  townships 

145.  Where  standard  parallels  have  been  placed  at  intervals 
of  30  or  36  miles,  under  practice  then  permissible,  and  present  con- 
ditions require  additional  standard  lines  from  which  to  initiate  new, 
or  upon  which  to  close  the  extension  of  old  surveys,  an  intermediate 


SYSTEM   OF   RECTANGULAR   SURVEYS.  137 

correction  line  should  be  established  to  which  a  local  name  may  be 
given,  e.  g.,  " Fifth  Auxiliary  Standard  Parallel  North,"  or  " Cedar 
Creek  Correction  Line,"  etc.,  and  the  same  will  be  run,  in  all  respects, 
like  a  regular  standard  parallel. 

GUIDE   MERIDIANS. 

146.  Guide  meridians  are  extended  north  from  the  base  line, 
or  standard  parallels,  at  intervals  of  24  miles  east  and  west  from 
the  principal  meridian,  in  the  manner  prescribed  for  running  the 
principal  meridian.     Under   all   conditions   the   guide   meridians 
will  be  terminated  at  the  points  of  their  intersections  with  the  stand- 
ard parallels;  the  guide  meridian  is  to  be  projected  on  the  true  meri- 
dian and  the  fractional  measurement  is  to  be  placed  in  the  last  half 
mile.    At  the  true  point  of  intersection  of  the  guide  meridian  with 
the  standard  parallel  a  closing  township  corner  is  to  be  established; 
the  parallel  will  be  retraced  between  the  first  standard  corners  east 
and  west  of  the  point  for  the  closing  corner,  in  order  to  determine 
the  exact  alinement  of  the  line  closed  upon,  and  the  distance  will 
be  measured  and  recorded  to  the  nearest  corner  on  eaid  standard 
parallel. 

147.  When  existing  conditions  require  that  such  guide  meridians 
shall  be  run  south  from  the  base  or  correction  lines,  they  will  be  ini- 
tiated at  the  theoretical  point  for  the  closing  corner  of  the  guide 
meridian,  which  will  be  calculated  on  the  basis  of  the  survey  of  the 
line  from  south  to  north  initiated  at  the  proper  standard  township 
corner.    At  the  theoretical  point  of  intersection  a  closing  township 
corner  will  be  established. 

148.  Where  guide  meridians  have  been  placed  at  intervals  ex- 
ceeding the  distance  of  24  miles,  and  new  governing  lines  are  re- 
quired in  order  to  limit  the  errors  of  the  old  or  to  control  new  sur- 
veys, a  new  guide  meridian  will  be  established,  and  a  local  name 
may  be  assigned  to  the  same,  e.  g.,  "Twelfth  Auxiliary  Guide  Merid- 
ian West, "  or  " Grass  Valley  Guide  Meridian, "  e tc .     These  auxiliary 
guide  meridians  will  be  surveyed  in  all  respects  like  regular  guide 
meridians. 

149.  The  above  scheme  covers  the  controlling  lines  contemplated 
under  the  rectangular  system,  and  results  regularly  in  the  survey  of 
quadrangles  bounded  on  the  north  and  south  by  true  parallels  of 
latitude,  and  on  the  east  and  west  by  true  meridians,  24  miles  apart. 
One  exception  may  now  be  noted  which  will  be  found  to  depart 

55465° — 19 10 


138  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

from  former  practice,  that  is,  where  a  guide  meridian  is  carried 
forward  at  a  time  when  uncertainty  exists  as  to  how  the  exterior  and 
sub  divisional  surveys  to  the  east  may  close  upon  it,  the  corners  upon 
the  same  will  be  marked  only  for  the  surveys  to  the  west. 

TOWNSHIP  EXTERIORS. 

REGULAR    ORDER. 

150.  The  controlling  factors  to  be  recognized  in  the  establishment 
of  new  township  boundary  lines  are  found  in  the  relation  of  these 
lines  to  the  new  subdivisional  surveys  which  are  to  be  executed. 
The  south  and  east  boundaries  are  normally  the  governing  lines  of 
the  subdivisional  surveys.     Defective  conditions  which  may  be 
found  in  previously  Established  exteriors  can  not  be  eliminated 
where  subdivisional  lines  have  been  initiated  from  or  closed  upon 
an  old  boundary,  but  the  errors  of  the  former  surveys  are  not  to  be 
incorporated  into  the  new,  and  where  the  previously  established 
south  and  east  boundaries  can  not  on  that  account  be  used  to  govern 
the  subdivision  of  the  adjoining  township,  other  controlling  lines 
known  as  the  sectional  correction  line  and  the  sectional  guide 
meridian,  hereinafter  described,  will  be  employed  as  expedient.    A 
new  meridional  township  exterior  is  normally  the  governing  bound- 
ary of  the  township  to  the  west,  and  a  new  latitudinal  township 
exterior  is  normally  the  governing  boundary  of  the  township  to  the 
north;  any  new  boundary  should  therefore  be  established  with  full 
consideration  for  its  control  ur>on  the  sub  di  visional  surveys  there- 
after to  be  executed. 

151.  Whenever  practicable  the  township  exteriors  will  be  sur- 
veyed successively  through  a  quadrangle  in  ranges  of  townships, 
beginning  with  the  townships  on  the  south.     The  meridional  bound- 
aries of  the  townships  will  have  precedence  in  the  order  of  survey 
and  will  be  run  from  south  to  north  on  true  meridians;  quarter- 
section  and  section  corners  will  be  established  alternately  at  intervals 
of  40  chains,  and  meander  corners  at  the  intersection  of  the  line  with 
all  meanderable  bodies  of  water;  a  temporary  township  corner  will 
be  set  at  a  distance  of  480  chains,  pending  a  determination  of  the 
controlling  factor  upon  which  its  final  position  will  be  governed, 
whereupon  the  temporary  point  will  be  replaced  by  a  permanent 
corner  in  proper  latitudinal  position.     The  latitudinal  township 
boundary  will  be  run  first  as  a  random  line,  setting  temporary 
corners,  on  a  cardinal  course,  from  the  old  toward  the  new  meridional 
boundary,  and  corrected  back  on  a  true  line  if  ideal  conditions  are 


SYSTEM   OF  RECTA IsGULAK   SURVEYS. 


139 


f.g.17. 

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140 


MANUAL,  OF  SURVEYING  INSTRUCTIONS.    " 


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SYSTEM  OF  RECTANGULAR  SURVEYS. 


141 


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142  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

found  to  obtain.  Where  both  meridional  boundaries  are  new  lines 
or  where  both  have  been  previously  established,  the  random  lati- 
tudinal boundary  will  be  run  from  east  to  west.  In  either  case,  if 
defective  conditions  are  not  encountered,  the  random  line  will  be 
corrected  back  on  a  true  line,  upon  which  will  be  established  regu- 
lar quarter-section  and  section  corners  at  intervals  of  40  chains, 
alternately,  counting  from  the  east,  and  meander  corners  at  the 
intersection  of  the  true  line  with  all  meanderable  bodies  of  water. 
The  bearing  of  the  true  line  will  be  calculated  on  the  basis  of  the 
falling  of  the  random,  and  the  fractional  measurement  will  be  placed 
in  the  west  half  mile.  A  meridional  township  exterior  will  be 
terminated  at  the  point  of  its  intersection  with  a  standard  parallel, 
placing  the  excess  or  deficiency  in  measurement  in  the  northern- 
most half  mile.  At  the  point  of  intersection  of  the  meridional 
boundary  with  a  standard  parallel  a  closing  township  corner  will  be 
established;  the  parallel  will  be  retraced  between  the  first  standard 
corners  east  and  west  of  the  point  for  the  closing  corner,  in  order  to 
determine  the  exact  alinement  of  the  line  closed  upon,  and  the 
distance  will  be  measured  and  recorded  to  the  nearest  corner  on  said 
standard  parallel. 

152.  In  order  to  complete  the  exteriors  of  a  township  it  will  often 
remain  to  establish  a  meridional  boundary  between  previously  estab- 
lished township  corners;  such  boundaries  will  be  run  from  south  to 
north  on  random  lines,  with  temporary  corners  set  at  intervals  of 
40  chains,  and,  if  defective  conditions  are  not  encountered,  the 
random  will  be  corrected  to  a  true  line;  by  this  plan  the  excess  or 
deficiency  of  measurement  will  be  placed  in  the  north  half  mile,  as 
required  by  law,  and  double  sets  of  corners  will  be  avoided  where 
unnecessary. 

153.  The  temporary  points  on  any  random  exterior  will  be  re- 
placed by  permanent  corners,  in  proper  position,  when  the  final  true 
line  adjustments  for  the  latter  have  been  fully  determined;  the 
true  line  will  be  properly  blazed  "through  timber,  and  distances  to 
important  items  of  topography  will  be  adjusted  to  correct  true 
line  measurements. 

154.  The  field  notes  will  embrace  a  full  and  complete  record  of 
the  manner  in  which  the  township  exteriors  are  run  and  established. 
The  notes  will  show  how  the  alinement  of  the  random  latitudinal 
curve  was  determined,  the  direction  of  the  projection,  the  amount 
of  the  falling  north  or  south  oi  the  objective  township  corner,  and  the 
calculated  return  course  or  true  line. 


SYSTEM   OF   RECTANGULAR   SURVEYS.  143 

IRREGULAR    ORDER   AN-D   PARTIAL   SURVEYS. 

155.  As  the  remaining  unsurveyed  public  lands  are  found  to  con- 
tain less  and  less  extensive  areas  surveyable  under  the  law  it  becomes 
necessary  to  depart  from  the  ideal  procedure  in  order  more  directly 
to  reach  the  areas  authorized  for  survey.    The  many  possible  com- 
binations are  entirely  too  numerous  to  state  in  detail,  but  where  an 
irregular  order  appears  to  be  necessary  such  departure  from  the 
ideal  order  of  survey  will  be  specifically  outlined  in  the  written 
special  instructions.     Such  departure  should  always  be  based  on  the 
principle  of  accomplishing,  by  whatever  plan,  the  same  relation  of 
one  township  boundary  to  another  as  would  have  resulted  from 
regular  establishment  under  ideal  conditions. 

In  authorizing  surveys  to  be  executed  it  will  not  usually  be  pro- 
vided that  exteriors  are  to  be  carried  forward  until  the  township  is 
to  be  subdivided ;  thus  where  causes  operate  to  prevent  the  establish- 
ment of  the  boundaries  in  full  it  is  not  imperative  that  the  survey  of 
the  exterior  lines  be  completed;  under  such  conditions  it  may  be 
found  necessary  to  run  section  lines  as  offsets  to  township  exteriors 
and  such  section  lines  will  be  run  either  on  cardinal  courses  or 
parallel  to  the  governing  boundaries  of  such  townships,  or  even 
established  when  subdividing,  as  existing  conditions  may  require. 

GENERAL    EXCEPTIONS. 

156.  The  above  rules  accord  with  former  practice,  except  that  in 
certain  instances  the  random  latitudinal  boundaries  will  be  run 
from  west  to  east,  instead  of  invariably  from  east  to  west,  as  here- 
tofore required.     It  is  also  deemed  advisable  to  incorporate  other 
exceptions  which  will  lessen  the  difficulties  of  subdivisional  surveys 
frequently  experienced  in  the  past. 

It  is  especially  desirable  that  the  alinement  of  a  new  latitudinal 
boundary  (which  becomes  the  governing  south  boundary  of  the 
township  to  the  north)  shall  not  depart  more  than  14'  from  the  true 
cardinal  course;  therefore  the  random  line,  run  upon  the  cardinal 
course,  may  be  made  the  true  line  where  the  falling  would  require 
a  correction  exceeding  14'  of  arc.  Where  the  random  latitudinal 
boundary  thus  closes  on  a  new  meridional  exterior  the  temporary 
township  corner  may  be  adjusted  to  the  latitude  of  the  opposite 
township  corner;  but  where  both  meridional  boundaries  have  been 
previously  surveyed  a  closing  township  corner  will  be  established 
at  the  point  of  intersection  of  the  random  latitudinal  line  with  the 


144 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


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SYSTEM   OF   RECTANGULAR   SURVEYS. 


145 


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MANUAL  OF  SURVEYING  INSTRUCTIONS. 


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Fig.28. 


SYSTEM:  OF  RECTANGULAR  SUR\TEYS. 


147 


meridional  boundary,  or  its  projection  to  the  north  or  south  as  the 
case  may  be.  Likewise,  where  a  meridional  boundary  is  run  as  a 
random,  the  random  will  be  made  the  true  line  if  the  adjustment  for 
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Fig.29. 


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Latitude  70°N. 

Illustrating  the  adjustment  in  the  direction  of  the  meridional  lines  of  a  subdivi- 
sional  survey  on  account  of  convergency  of  meridians,  also  the  14'  limit  of  the 
rectangular  "safety  zone." 

onal  subdivisional  lines  (on  account  of  convergency  of  meridians) 
would  result  in  calculated  bearings  (in  the  northernmost  miles  of 
the  latter  lines)  in  excess  of  147  from  cardinal.  This  margin  for  the 
alinement  of  the  random  and  true  meridional  lines  of  the  subdivi- 
sional survey  calls  for  a  governing  east  boundary  whose  bearing  will 


.48  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

all  within  certain  extremes  suited  to  the  latitude  of  the  township, 
,s  for  example  (see  second  part  of  Table  2,  Standard  Field  Tables) : 

Latitude  25°  N. 

stMi.  Mer.  Subdv.  N.  0°  14'  E.   5th  Mi.  Her.  Subdv.  N.  0°  14'  W. 
)orr.  for  Conv.  +00          Oorr.  for  Conv.  —02 


5.  bdy.  may  be         N.  0°  14X  E.   E.  bdy.  may  be          N.  0°  12'  W. 
Latitude  70°  N. 

st  Mi.  Mer.  Subdv.  X.  0°  14'  E.   5th  Mi.  Mer.  Subdv.  N.  0°  14'  W. 
)prr.  for  Conv.  +02          Corr.  for  Conv.  -10 


S.  bdy.  may  be         N.  0°  W  E.    E.  bdy.  may  be          N.  0°04/ W. 

It  will  be  noted  that  the  above  text  in  reference  to  the  14'  limit  for 
ixteriors  applies  only  to  the  establishment  of  new  boundaries. 
L  previously  established  boundary  every  part  of  which  is  within  21' 
>f  cardinal  will  not  be  considered  defective  in  alinement.  Even  in 
he  case  of  new  exteriors,  where  the  surveyor  who  establishes  such 
ine  is  also  to  subdivide  the  township  of  which  such  exterior  is  a 
;overning  boundary,  the  margin  of  14X  may  be  exceeded  to  a  limited 
ixtent  if  the  surveyor  is  satisfied  that  existing  conditions  favor  keep- 
ng  within  the  21'  limit  in  the  sub  divisional  survey.  Thus  it  will  be 
een  that  the  purpose  of  the  14'  limit  is  merely  to  facilitate  the  estab- 
ishment  of  all  subdi visional  lines  within  the  prescribed  definite 
imit  of  2V  from  cardinal. 

157.  Another  general  exception  may  be  noted  where  uncertainty 
sxists  as  to  how  unsurveyed  exteriors  and  sub  divisional  lines  will 
lose  upon  the  newly  established  boundaries,  in  which  case  the  cor- 
kers thereon  may  be  marked  only  for  the  townships  of  which  the 
lew  exteriors  control  the  subdivisions. 

COMPLETION   OF   PARTIALLY   SURVEYED    EXTERIORS. 

158.  Where  the  end  portions  of  a  township  exterior  have  been 
xreviotisly  surveyed  and  closed  upon,  the  fractional  unsurveyed 
ruddle  part  will  be  completed  by  random  and  true  line,  without 
>ffset  regardless  of  the  deviation  from  cardinal;  the  fractional  meas- 
irements  will  be  placed  as  a  general  rule  in  the  north  and  west 
lalf  miles,  thereby  permitting  the  sub  divisional  lines  to  be  extended 
is  usual  from  the  south  to  the  north  and  from  the  east  to  the  west. 
[n  the  case  of  a  fractional  part  of  an  exterior  remaining  unsurveyed 


SYSTEM  OF  RECTANGULAR   SURVEYS. 


149 


at  either  end  of  the  line,  the  boundary  will  be  completed  by  random 
line,  initiated  at  the  previously,  established  terminal  monument, 
which  will  be  projected  on  a  cardinal  course  in  the  direction  of  the 
objective  township  corner.  The  random  will  be  corrected  to  a 
true  line  where  the  calculated  bearing  of  any  subdi visional  line, 
governed  by  such  exterior,  comes  within  14'  from  cardinal,  and  the 


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fractional  measurement  will  be  placed  generally  in  the  north  or 
west  half  miles.  However,  should  irregularity  be  developed,  or 
in  the  absence  of  a  previously  established  objective  township  corner, 
the  partially  surveyed  exteriors  will  be  completed  on  cardinal 
courses  beginning  as  above;  and  in  either  case  the  fractional  meas- 
urements will  generally  be  placed  in  the  north  and  west  half  miles. 


150  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

RETEACEMENTS    BEFORE    SUBDIVIDING. 

159.  If  any  part  or  all  of  the  boundaries  of  a  township  which 
is  to  be  subdivided  have  been  previously  surveyed,  and  the  proper 
supervising  officer  has  reason  to  question  the  accuracy  of  any  portion 
of  such  exteriors,  or  the  condition  of  the  corner  monuments  thereon, 
the  fact  will  be  stated  in  the  written  special  instructions,  and  the 
surveyor  will  be  authorized  and  required,  as  a  condition  precedent 
to  beginning  the  subdivisional  survey  of  such  township,  to  retrace 
such  boundaries  in  order  to  determine  the  true  alinement  and  lengths 
of  the  lines,  to  rebuild  any  corners  found  to  be  in  a  poor  condition, 
and  otherwise  to  accomplish  the  following  purposes: 

(a)  To  locate  all  material  errors,  (6)  to  test  every  line  as  to  what 
alterations  may  be  required,  and  (c)  to  determine  all  data  necessary 
for  the  computation  of  the  areas  of  all  fractional  lots. 

160.  All  data  obtained  in  the  retracements  will  be  embodied  in 
the  field  notes  and  shown  upon  the  plat  of  the  survey,  unless  the 
retracement  results  are  in  substantial  agreement  with  the  record  of 
the  original  survey,  in  which  case  a  general  statement  to  that  effect 
may  be  made  in  the  field  notes,  and  the  original  record  may  be  per- 
mitted to  govern  the  data  to  be  placed  upon  the  plat. 

RECTANGULAR   LIMITS. 

161.  Before  approaching  the  subject  of 1 1  subdivision  of  townships  " 
it  is  necessary  to  consider  the  requirement  of  law  relative  to  rectan- 
gular surveys,  wherein  the  square  mile,  or  section,  is  the  unit  of 
subdivision.     The  normal  township  will  include  36  sections  in  all, 
25  of  which  are  returned  as  containing  640  acres  each;  10  sections  (on 
the  north  and  west  boundaries)  each  contain  regular  aliquot  parts 
totaling  480  acres  with  4  additional  fractional  lets  in  each  section, 
each  lot  containing  40  acres  plus  or  minus  definite  differences  to  be 
determined  in  the  survey;  and,  section  6  containing  regular  aliquot 
parts  totaling  360  acres  with  7  additional  fractional  lots  each  con- 
taining 40  acres  plus  or  minus  certain  definite  differences  to  be 
determined  in  the  survey,  all  as  contemplated  by  law.     The  afore- 
mentioned aliquot  parts  of  640  acres  may  be  termed  "regular  or  legal 
subdivisions  of  a  section,"  as  a  quarter  section,  a  half-quarter  section, 
or  a  quarter-quarter  section,  the  legal  minimum  of  which,  for  purposes 
of  disposal  under  the  general  land  laws,  is  40  acres. 

162.  In  the  administration  of  the  surveying  laws  it  has  been 
necessary  to  establish  a  definite  relation  between  rectangularity 


SYSTEM  OF  RECTANGULAR  SURVEYS. 

Fig.31. 


151 


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152  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

(square  miles  of  640  acres,  or  aliquot  parts  thereof),  as  contemplated 
by  law,  and  the  resulting  unit  of  subdivision  consequent  Upon  the 
practical  application  of  surveying  theory  to  the  marking  out  of 
the  lines  on  the  earth's  surface,  wherein  the  ideal  section  is 
allowed  to  give  way  to  one  which  may  be  termed  " regular."  Such 
relation,  as  applied  to  the  boundaries  of  a  section,  has  been  placed 
at  the  following  limits: 

(a)  For  alinement,  not  to  exceed  2V  from  cardinal  in  any  part; 
(6)  for  measurement,  the  distance  between  regular  corners  to  be 
normal  according  to  the  plan  of  survey,  with  certain  allowable 
adjustments  not  to  exceed  25  links  in  40  chains;  and  (c)  for  closure, 
not  to  exceed  50  links  in  either  latitude  or  departure. 

Township  exteriors,  or  portions  thereof,  will  be  considered  de- 
fective when  they  do  not  qualify  within  the  above  limits.  It  is  also 
necessary,  in  order  to  subdivide  a  township  regularly,  to  consider  a 
fourth  limit,  as  follows: 

(d)  For  position,  the  corresponding  section  corners  upon  the  op- 
posite boundaries  of  the  township  to  be  so  located  that  they  may  be 
connected  by  true  lines  which  will  not  deviate  more  than  21'  from 
cardinal. 

A  previously  established  exterior  will  not  be  considered  de- 
fective if  the  above  limits  are  satisfied,  and  a  subdivisional  survey 
may  proceed  in  safety  if  the  rectangular  limits  (in  such  subdivisional 
survey)  are  not  exceeded.  On  the  other  hand,  if  the  conditions 
relating  to  the  previously  established  governing  boundaries  are  such 
that  the  rectangular  limits  have  already  been  exceeded  or  that  the 
danger  point  is  likely  to  be  reached  at  an  early  stage  in  the  subdi- 
visional survey,  the  necessary  corrective  steps  will  be  taken  before 
subdividing,  as  hereinafter  described. 

RECTIFICATION  OP  DEFECTIVE  EXTERIORS  BEFORE  SUBDIVIDING  AND 
METHOD  OF  ESTABLISHING  NEW  GOVERNING  BOUNDARIES  WHERE 
THE  PREVIOUSLY  SURVEYED  EXTERIORS  ARE  FOUND  TO  BE  DE- 
FECTIVE. 

163.  Where  subdivisional  lines  have  been  initiated  from  or  closed 
upon  an  lexterior  prior  to  the  subdivision  of  one  of  the  adjoining 
townships,  its  alinement  can  not  legally  be  changed.  A  defective 
boundary  not  so  closed  upon  may  be  obliterated,  after  connecting 
the  old  with  the  new  monuments,  Y/hereupon  a  new  boundary  will 
be  projected  in  accordance  with  regular  methods.  If  a  legal  claim 
of  any  character  such  as  mineral,  forest-homestead,  small-holding, 


SYSTEM   OF  RECTANGULAR   SURVEYS. 


153 


Fig.33. 

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154  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

railroad  or  canal  right-of-way,  reservoir  site,  etc.,  has  been  connected 
with  any  corner  on  an  exterior  which  may  be  subject  to  rectification, 
the  fact  will  be  specifically  stated  in  the  written  special  instructions, 
and  in  case  such  exterior  is  found  to  be  defective  the  surveyor  will 
accurately  connect  the  old  corner  by  course  and  distance  with  the 
new  monument.  Such  old  corners  will  not  be  destroyed,  but  the 
letters  "W  P"  (signifying  "witness  point")  will  be  distinctly  added 
to  the  original  markings.  A  complete  record  of  the  connection  from 
the  new  to  the  old  monument,  a  description  of  the  latter  and  its 
accessories,  and  the  new  markings,  will  be  included  in  the  field 
notes,  and  the  position  of  the  old  monument  will  be  shown  on  the 
plat  of  the  survey. 

164.  If  a  boundary  is  defective  in  measurement  or  position  and  is 
not  subject  to  rectification,  the  location  of  the  original  corners  will 
not  be  changed,  but  the  marks  thereon,  and  the  marks  upon  or 
position  of  the  accessories,  may  be  appropriately  altered  to  stand 
only  for  the  sections  of  the  previously  established  surveys.     New 
corners  to  control  the  surveys  of  the  adjoining  township  may  then 
be  established  on  the  old  line,  but  at  regular  distances  of  40  and  80 
chains.     Where  new  corners  are  placed  on  an  oblique  exterior  (one 
whose  bearing  departs  more  than  1°  from  cardinal)  the  same  will  be 
so  located  for  measurement  that  the  oblique  distance  multiplied 
by  the  cosine  or  sine  of  the  bearing  angle,,  as  the  case  may  be,  will 
result  in  cardinal  equivalents  of  40  and  80  chains. 

165.  Where   subdi visional   lines   have   been   initiated   from   or 
closed  upon  one  side  of  a  portion  of  a  township  boundary  prior  to 
the  subdivision  of  the  township  on  the  opposite  side,  while  upon 
the  remaining  portion  of  the  same  such  conditions  do  not  interfere, 
said  remaining  portion  may  be  obliterated,  if  found  defective, 
whereupon  a  new  line  will  be  projected  in  accordance  with  regular 
methods. 

166..  The  position  of  the  new  exteriors,  or  of  new  corners  on 
defective  township  boundaries  must  be  established  by  an  actual 
rerunning  of  such  lines;  the  data  acquired  in  surveying  subdivisional 
lines  closing  upon  defective  exteriors  can  not  be  accepted  in  lieu 
of  such  retracement  or  resurvey. 

167.  Instances  will  occur  both  in  closing  subdivisional  surveys 
upon  regular  exteriors  and  in  the  retracement  of  defective  bound- 
aries not  subject  to  rectification  where  it  will  be  developed  that  the 
original  monuments  have  become  lost  or  obliterated,  or  where  such 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


Fig.  35. 


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156  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

corners  may  be  identified  in  an  advanced  state  of  deterioration.  All 
such  exterior  corners  will  be  reestablished  and  remonumented  in 
their  correct  original  positions  in  strict  accordance  with  the  pro- 
visions of  Chapters  IV  and  V,  and  a  complete  record  thereof  will  be 
embodied  in  the  field  notes. 

188.  The  south  boundary  of  a  township  is  regularly  the  govern- 
ing latitudinal  boundary  and  will  be  used  as  such  unless  defective 
in  alinement:  if  defective  in  measurement,  and  not  subject  to  rec- 
tification, the  position  of  the  original  corners  will  not  be  changed, 
but  the  marks  thereon  and  the  accessories  will  be  appropriately 
altered  to  stand  only  for  the  sections  of  the  township  to  the  south; 
new  corners  of  two  sections  and  quarter-section  corners  common  to 
the  sections  of  the  township  to  the  north  will  be  established  at  reg- 
ular intervals  of  40  chains,  counting  from  the  east,  and  the  excess 
or  deficiency  in  measurement  placed  in  the  west  half  mile.  If  the 
south  boundary  is  defective  in  alinement,  a  sectional  correction 
line  will  be  required. 

169.  The  east  boundary  of  a  township  is  regularly  the  governing 
meridional  boundary  and  will  be  used  as  such  unless  defective  in 
alinement;  if  defective  in  measurement,  and  not  subject  to  rectifi- 
cation, the  position  of  the  original  corners  will  not  be  changed,  but 
the  marks  thereon  and  the  accessories  will  be  appropriately  altered 
to  stand  only  for  the  sections  of  the  township  to  the  east;  new  cor- 
ners of  two  sections  and  quarter-section  corners  common  to  the  sec- 
tions of  the  township  to  the  west  will  be  established  at  regular  inter- 
vals of  40  chains,  counting  from  the  south.     If  the  east  boundary  is 
def ective  in  alinement  a  sectional  guide  meridian  will  be  required . 

170.  New  west  and  north  boundaries  of  a  township  become  the 
governing  meridional  and  latitudinal  boundaries  of  the  townships 
to  the  west  and  north,  respectively,  and  are  required  to  be  properly 
established  as  such. 

171.  New  east  and  south  boundaries  of  a  township  become  the 
closing  meridional  and  latitudinal  boundaries  of  the  townships  to 
the  east  and  south,  respectively,  and  where  by  peculiar  necessity 
the  ideal  plan  must  be  modified  and  doubt  exists  as  to  how  unsur- 
veyed  lines  may  close  upon  same,  the  corners  thereon  may  be  estab- 
lished common  only  to  the  sections  of  the  township  of  which  the 
new  lines  are  the  governing  boundaries.     The  corners  appropriate 
to  the  sections  upon  the  opposite  side  will  be  duly  established  as 
closing  corners  at  the  time  of  the  survey  of  the  subdivisional  lines 


SYSTEM  OF  RECTANGULAR  SURVKY 


157 


Fig.  3  7. 


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5.  bdy.  defective  in  measurement.  Double  set  of  corners. 

IBS 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


of  the  adjoining  townships  if  the  original  corners  are  then  found  to 
be  defective  in  position,  and  where  regular  connections  can  be 
made  the  marks  upon  the  original  corners  will  be  appropriately 
altered  to  corners  of  maximum  control. 


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Fig.  39. 

172.  \Yhere  the  previously  established  north  or  west  bounda- 
ries are  found  to  be  defective  in  measurement  or  position  and  sub- 
divisional  surveys  in  the  adjoining  townships  have  been  initiated 
upon  the  same,  thereby  preventing  rectification,  the  marks  upon 
the  original  corners  will  be  appropriately  altered  to  corners  of  two 
sections  and  quarter-section  corners  common  only  to  the  sections  of 


SYSTEM  OF  RECTANGULAR  SURVEYS.  l.'/J 

the  townships  to  the  north  or  west,  respectively.  Closing  section 
corners  will  be  established  when  subdividing  and  the  distance  meas- 
ured to  an  original  corner;  new  quarter-section  corners,  common  to 
the  sections  of  the  township  which  is  being  subdivided,  will  be 
placed  on  the  old  line  at  the  mean  distances  between  the  closing 
section  comers,  or  at  40  chains  from  one  direction,  depending  upon 
the  plan  of  the  subdivision  of  the  section.  Where  such  previously 
established  north  and  west  boundaries  are  defective  in  alinement, 
but  not  in  measurement  or  position,  no  changes  are  required,  and 
the  section  lines  of  the  township  which  is  being  subdivided  will  be 
connected  regularly  to  the  original  corners;  the  resulting  fractional 
measurements  will  be  placed  uniformly  in  the  north  and  west  half 
miles. 

173c  The  diagrams  which  accompany  the  text  illustrate  the  guid- 
ing principles  involved  in  the  method  of  establishing  new  govern- 
ing boundaries  where  the  previously  surveyed  exteriors  are  found 
to  be  defective.  Each  diagram  illustrates  a  simple  condition  affect- 
ing one  boundary  only,  and  the  examples  are  taken  only  from  the 
regular  order  of  procedure.  Combinations  of  two  or  more  of  the 
simple  defective  conditions  are  best  solved  by  an  analysis  of  the 
complex  problem  into  its  several  parts  of  simple  defective  condi- 
tions. The  same  statement  is  applicable  to  the  solution  of  complex 
defective  conditions  encountered  in  the  establishment  of  township 
exteriors  under  an  irregular  order  of  procedure.  The  surveyor  will 
be  expected  to  exercise  skill  and  judgment  in  dealing  with  similar 
field  problems,  but  where  extraordinary  conditions  are  encountered 
which  will  not  admit  of  analysis  and  solution  in  harmony  with  the 
principles  herein  set  forth  he  will  report  the  facts  to  the  proper 
supervising  officer  for  his  counsel. 

TABLES    OP  LATITUDES    AND    DEPARTURES    AND    CLOSING    ERRORS. 

174.  Upon  the  completion  of  the  survey  of  one  or  more  township 
exteriors  closing  the  figure  of  either  a  full  or  fractional  township,  a 
table  of  latitudes  and  departures  and  closing  errors  will  be  prepared, 
wherein  due  allowance  for  convergency  of  meridians  will  be  intro- 
duced. The  closing  errors  will  furnish  an  immediate  guide  to  the 
accuracy  of  the  lines  included  in  the  table  and,  in  case  the  limit  of 
closure  (-^  of  the  perimeter,  in  either  latitude  or  departure)  is  ex- 
ceeded, will  serve  to  show  what  additional  retracements  or  other 
corrective  steps  may  be  necessary  in  order  to  perfect  the  survey 


160  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

before  leaving  the  field.  The  table  of  latitudes  and  departures  and 
closing  errors,  including  every  part  of  any  closed  figure  embracing 
township  exteriors,  based  upon  final  field  determination  after  all 
necessary  retracements  and  final  true  lines  have  been  completed, 
will  be  incorporated  in  the  field  notes  of  the  survey.  The  general 
subject  of  " limits  of  closure"  will  be  amplified  hereinafter. 

SUBDIVISION   OF   TOWNSHIPS. 

REGULAR    BOUNDARIES. 

175.  The  boundaries  of  a  township  will  be  considered  within 
satisfactory  governing  limits  from  which  to  control  the  subdivisional 
survey  when  the  calculated  position  of  the  latter  lines  may  be  theo- 
retically projected  from  said  boundaries  without  invading  the  danger 
zone  in  respect  to  rectangular  limits  as  previously  described.    The 
danger  zone  has  already  been  placed  at  theoretical  bearings  exceed- 
ing 14X  from  cardinal,  and  the  corresponding  zone  in  respect  to 
lengths  of  lines  may  be  placed  at  theoretical  adjustments  exceeding 
33  links  per  mile. 

176.  The  direction  of  the  east  boundary  may  qualify  anywhere 
within  the  governing  limits  set  forth  under  the  subject  of  "  township 
exteriors,"  and  where  this  boundary  is  broken  in  alinement,  but 
otherwise  within  the  governing  limits,  its  mean  course  will  be 
adopted  when  considering  the  control  upon  the  direction  of  the 
meridional  subdivisional  lines. 

177.  The  subdivision  of  a  township  may  proceed  in  the  normal 
order,  where  the  above  conditions  are  satisfied,  as  follows: 

The  meridional  section  lines  will  be  initiated  at  the  regularly 
established  section  corners  on  the  south  boundary  of  the  township 
and  will  be  run  from  south  to  north  parallel  to  the  governing  east 
boundary,  or,  in  case  the  east  boundary  is  within  limits,  but  has 
been  found  by  retracement  to  be  imperfect  in  alinement,  the  merid- 
ional section  lines  will  be  run  parallel  to  the  mean  course  of  such  east 
boundary.  Regular  quarter-section  and  section  corners  will  be 
established  alternately  at  intervals  of  40  chains,  as  far  as  the  northern- 
most interior  section  corner.  The  last  miles  of  the  meridional  section 
lines  will  be  continued  as  random  lines,  each  successive  line  being 
run  parallel  to  the  true  east  boundary  of  the  section  to  which  it 
belongs;  a  temporary  quarter-section  corner  will  be  set  at  40  chains, 
the  distances  will  be  measured  to  the  points  of  intersection  of  the 
random  lines  with  the  north  boundary  of  the  township,  and  the 


SYSTEM   OF   RECTANGULAR   SURVEYS.  161 

fallings  of  the  random  lines  east  or  west  of  the  objective  section 
corners  will  be  noted.  The  randoms  will  then  be  corrected  to  true 
lines  by  returning  to  accomplish  the  required  markings  between  the 
section  corners,  including  the  permanent  establishment  of  the 
quarter-section  corners  on  the  true  lines  at  distances  of  40  chains 
from  the  south,  thus  placing  the  fractional  measurements  in  the  north 
half  miles.  The  bearings  of  the  true  lines  will  be  calculated  on  the 
basis  of  the  fallings  of  the  randoms  (see  Table  3,  Standard  Field 
Tables) .  Where  the  north  boundary  of  the  township  is  a  base  line  or 
standard  parallel,  the  last  miles  of  the  meridional  section  lines  will 
be  continued  as  true  lines  parallel  to  the  east  boundary  of  the  town- 
ship, setting  permanent  quarter-section  corners  at  40  chains  from 
the  south  and  closing  section  corners  at  the  points  of  intersection 
of  the  several  lines  with  the  base  or  standard  or  correction  line,  where 
the  distances  will  be  measured  to  the  nearest  corners  on  said  line. 
The  adjustment  of  the  bearing  of  all  meridional  section  lines  on 
account  of  convergency  of  meridians  has  already  been  explained  in 
Chapter  II. 

178.  The  latitudinal  section  lines,  except  in  the  west  range  of 
sections,  will  normally  be  run  from  west  to  east  on  random  lines 
parallel  to  the  south  boundaries  of  the  respective  sections,  setting 
temporary  quarter-section  corners  at  40  chains;  the  distances  will  be 
measured  to  the  points  of  intersection  of  the  random  lines  with  the 
north  and  south  lines  passing  through  the  objective  section  corners, 
and  the  fallings  of  the  random  lines  north  or  south  of  said  corners  will 
be  noted.    Each  random  will  be  corrected  to  a  true  line  by  returning 
to  accomplish  the  required  markings  between  the  section  corners, 
including  the  permanent  establishment  of  quarter-section  corners 
at  the  mid-points  on  the  true  lines.    The  bearings  of  the  true  lines 
will  be  calculated  on  the  basis  of  the  fallings  or  the  randoms  (see 
Table  3,  Standard  Field  Tables) .    In  the  west  range  of  sections  the 
random  latitudinal  section  lines  will  be  run  from  east  to  west,  parallel 
to  the  south  boundaries  of  the  respective  sections,  and  on  the  true 
lines  the  permanent  quarter-section  comers  will  be  established  at 
40  chains  from  the  east,  thus  placing  the  fractional  measurements  in 
the  west  half  miles. 

179.  Meander  corners  will  be  established  at  the  points  of  inter- 
section of  the  several  true  lines  with  all  meanderable  bodies  of  water. 

180.  The  meridional  section  lines  will  have  precedence  in  the 
order  of  execution,  and  these  will  be  surveyed  successively,  begin- 


162  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

ning  with  the  first  meridional  section  line  counting  from  the  east. 
A  meridional  section  line  will  not  be  continued  beyond  a  section 
corner  until  after  the  connecting  latitudinal  section  line  has  been 
surveyed,  and  in  the  case  of  the  fifth  meridional  section  line,  both 
latitudinal  section  lines  connecting  east  and  west  will  be  surveyed 
before  continuing  with  the  meridional  line  beyond  a  section 
corner.  The  successive  meridional  lines  may  be  taken  up  at  the 
convenience  of  the  surveyor  at  any  time  in  order  as  previously 
stated,  but  none  will  be  carried  beyond  uncompleted  sections  to  the 
east.  The  field  notes  will  be  compiled  in  ranges  of  sections  begin- 
ning with  the  easternmost,  and  the  west  two  ranges  will  be  compiled 
by  alternating  with  the  adjoining  east  and  west  sections.  The 
specimen  field  notes  exemplify  the  usual  order  of  survey  and  the 
prescribed  method  of  arranging  the  field  notes. 

181.  Thus,  to  recapitulate,  the  subdi visional  survey  will  be  com- 
menced at  the  corner  of  sections  35  and  36,  on  the  south  boundary  of 
the  township,  and  the  line  between  sections  35  and  36  will  be  run 
parallel  to  the  east  boundary  of  the  township,  or  to  the  mean  course 
thereof,  if  it  is  imperfect  in  alinement,  but  within  limits,  establish- 
ing the  quarter-section  corner  at  40  chains,  and  at  80  chains,  the  corner 
of  sections  25,  26,  35  and  36.  From  the  last-named  corner,  a  random 
line  will  be  run  eastward,  without  blazing,  parallel  to  the  south 
boundary  of  section  36,  to  its  intersection  with  the  east  boundary  of 
the  township,  placing  at  40  chains  from  the  point  of  beginning,  a  post 
for  temporary  quarter-section  corner.  If  the  random  line  intersects 
said  township  boundary  exactly  at  the  corner  of  sections  25  and  36, 
it  will  be  blazed  back  and  established  as  the  true  line,  the  permanent 
quarter-section  corner  being  established  thereon,  midway  between 
the  initial  and  terminal  section  corners.  If  the  random  intersects 
said  township  boundary  to  the  north  or  south  of  said  corner,  the 
falling  will  be  carefully  measured,  and  from  the  data  thus  obtained, 
the  true  return  course  will  be  calculated,  and  the  true  line  blazed 
and  established,  and  the  position  of  the  quarter-section  corner 
determined,  as  directed  above.  The  meridional  section  line  will 
be  continued  on  the  same  plan,  likewise  the  successive  latitudinal 
section  lines  except  that  each  random  will  be  run  parallel  to  the  true 
south  boundary  of  the  section  to  which  it  belongs.  After  having 
established  the  west  and  north  boundaries  of  section  12,  the  line 
between  sections  1  and  2  will  be  projected  northward,  on  a  random 
line,  parallel  to  the  east  boundary  of  the  township,  or  to  its  mean 


SYSTEM  OF  RECTANGULAR   SURVEYS. 


163 


course,  as  the  case  may  be,  setting  a  post  for  temporary  quarter-sec- 
tion corner  at  40  chains,  to  its  intersection  with  the  north  boundary 
of  the  township.  If  the  random  intersects  said  north  boundary 
,  exactly  at  the  corner  of  sections  1  and  2,  it  will  be  blazed  back  and 
established  as  the  true  line,  the  quarter-section  corner  being  estab- 
lished permanently  in  its  original  temporary  position,  and  the  frac- 
tional measurement  thrown  into  that  portion  of  the  line  between  the 


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FIG.  40.— The  numbers  on  the  section  lines  indicate  the  normal  order  of  sub- 
division and  arrangement  of  the  field  notes. 

permanent  quarter-section  corner  and  the  north  boundary  of  the 
township.  If,  however,  said  random  intersects  the  north  boundary 
of  the  township,  to  the  east  or  west  of  the  corner  of  sections  1  and  2, 
the  falling  will  be  carefully  measured,  and  from  the  data  thus 
obtained  the  true  return  course  will  be  calculated  and  the  true  line 
established,  the  permanent  quarter-section  corner  being  placed 'upon 
the  same  at  40  chains  from  the  initial  corner  of  the  random  line, 


164  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

thereby  throwing  the  fractional  measurement  in  that  portion  lying 
between  the  quarter-section  corner  and  the  north  boundary  of  the 
township.  When  the  north  boundary  of  a  township  is  a  base  line 
or  standard  parallel,  the  line  between  sections  1  and  2  will  be  run  , 
as  a  true  line  parallel  to  the  east  boundary  of  the  township,  or  to  its 
mean  course,  as  the  case  may  be;  the  quarter-section  corner  will  be 
placed  at  40  chains,  and  a  closing  corner  will  be  established  at  the 
point  of  intersection  with  such  base  or  standard  line ;  and  in  such  case, 
the  distance  from  said  closing  corner,  to  the  nearest  standard  corner 
on  such  base  or  standard  line,  will  be  carefully  measured  and  noted. 
The  successive  ranges  of  sections  proceeding  from  east  to  west  will 
be  surveyed  in  the  same  manner;  then  after  having  established  the 
west  and  north  boundaries  of  section  32,  a  random  line  will  be 
initiated  at  the  corner  of  sections  29,  30,  31  and  32,  which  will  be 
projected  westward  parallel  to  the  south  boundary  of  the  township, 
setting  a  temporary  quarter-section  corner  at  40  chains,  to  an  inter- 
section with  the  west  boundary  of  the  township,  where  the  falling 
will  be  measured  and  the  bearing  of  the  true  line  calculated,  where- 
upon the  line  between  sections  30  and  31  will  be  permanently 
marked  between  the  section  corners,  and  the  quarter-section  corner 
thereon  will  be  established  at  40  chains  from  the  east,  thereby  placing 
the  fractional  measurement  in  the  west  half  mile  as  required  by  law. 
The  survey  of  the  west  two  ranges  of  sections  will  be  continued  on 
the  same  plan,  and  the  random  line  between  sections  6  and  7  will  be 
run  westward  parallel  to  the  true  line  between  sections  7  and  18; 
the  random  will  be  corrected  to  a  true  line  and  the  fractional  measure- 
ment placed  in  the  west  half  mile ;  finally  the  random  line  betAveen 
sections  5  and  6  will  be  run  northward  parallel  to  the  true  line 
between  sections  4  and  5 ;  the  random  will  be  corrected  to  a  true  line 
and  the  fractional  measurement  placed  in  the  north  half  mile. 

It  may  well  be  noted  again  that  the  meridional  section  lines  are 
surveyed  as  true  lines  for  5  miles,  i.  e.,  the  lines  are  surveyed 
and  permanently  monumented  in  the  first  instance  without  later 
adjustment.  Every  means  is  placed  at  the  disposal  of  the  surveyor 
by  which  he  is  expected  to  accomplish  accurate  results,  and  the 
system  of  survey  provides  amply  for  the  adjustment  of  all  reasonable 
closing  errors.  Thus,  a  slight  error  in  the  alinement  of  the  meridional 
section  lines  is  taken  up  in  the  measurement  of  the  latitudinal  lines 
which,  in  order  to  come  within  the  rectangular  limit,  must  be 
within  50  links  of  80  chains  in  length,  except  in  the  west  range  of 


SYSTEM   OF   RECTANGULAR    SURVEYS.  165 

sections  where  the  convergency  of  the  meridional  lines  is  regularly 
provided  for;  the  accumulated  error  in  alinement  for  the  5  miles  of 
true  meridional  line  is  taken  up  in  the  sixth  mile,  which  is  run 
random  and  true ;  here  the  true  line  must  be  within  21'  of  cardinal 
in  order  to  come  within  the  rectangular  limit.  The  slight,  ordinary 
errors  in  the  measurement  of  the  meridional  section  lines  are  taken 
up  by  the  adjustment  of  the  bearings  of  the  latitudinal  section  lines 
which,  in  order  to  come  within  the  rectangular  limit,  must  be  within 
21X  of  cardinal;  the  accumulated  error  in  measurement  in  running 
north  is  placed  in  the  la.st  fractional  half  mile ;  here  the  meridional 
distance  will  be  checked  by  a  calculated  closing  around  the  last 
section,  and  the  latitudinal  error  must  not  exceed  50  links  (or  -^) 
in  order  to  come  within  the  usual  limits  of  closure.  The  accuracy  of 
the  subdivisional  survey  will  everywhere  be  tested  by  the  usual 
rules  for  limits  of  closure,  hereinafter  described.  The  surveyor 
should  discriminate  carefully  between  the  limits  for  subdivision 
and  limits  of  closure  and  note  with  due  respect  that  whereas  the 
latter  may  admit  of  differences  as  great  as  50  links  in  any  one  section, 
the  former  are  controlled  by  the  limit  of  rectangularity  and  will  be 
exceeded  if  the  accumulative  error  is  greater  than  3JX  in  alinement, 
or  8J-  links  per  mile  in  measurement.  The  accumulative  error  must 
ever  be  guarded  against  and  avoided,  and  the  order  of  survey  is 
arranged  with  a  view  to  furnishing  continuous  checks  upon  the 
accuracy  of  all  lines. 

182.  Any  random  subdivisional  line  may  be  run  for  distance  only 
where  the  objective  section  corner  is  in  sight,  but  the  bearing  will 
be  recorded,  and  the  usual  rules  for  running  random  and  true  lines 
will  be  duly  observed  in  every  other  respect.  The  random  latitudinal 
section  lines,  except  in  the  west  range  of  sections,  will  normally 
be  run  from  west  to  east,  thus  always  closing  Tipon  a  previously 
established  section  corner;  but  when  under  the  exigencies  of  the  field 
work,  in  order  to  economize  the  time  of  his  party,  the  surveyor  may 
elect  to  project  the  random  from  east  to  west  (always  parallel  to  the 
south  boundary  of  the  section),  a  temporary  section  corner  (if  the 
permanent  corner  has  not  already  been  established)  will  be  set  at 
80  chains,  and  the  true  point  for  the  section  corner  will  be  determined 
as  usual  at  the  80-chain  point  on  the  meridional  section  line,  where- 
upon the  connection  of  the  random  latitudinal  line  and  the  perma- 
nent marking  of  the  true  line  will  be  completed  as  regularly  provided. 
Examples  of  the  authorized  rules  for  running  subdivisional  lines  will 
be  found  in  the  specimen  field  notes. 


166  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

IRREGULAR    BOUNDARIES. 

183.  Where  either  of  the  governing  boundaries  of  a  township  is 
disqualified  as  a  controlling  line  upon  which  to  initiate  a  subdivi- 
sional  survey,  the  necessary  retracements  and  resurveys  or  altera- 
tions   will    be    accomplished    before    subdividing    as    previously 
explained  under  the  subject  of  township  exteriors;  thus  may  be 
assured  every  possible  provision  for  a  correct  subdi visional  survey 
except  as  either  the  south  or  the  east  boundary  may  be  defective  in 
alinement  and  not  subject  to  rectification. 

SECTIONAL   GUIDE    MERIDIAN. 

184.  If  the  east  boundary  of  the  township  is  defective  in  aline- 
ment, and  can  not  be  rectified,  and  the  north  boundary  is  thus  made 
defective  in  position,  the  first  meridional  section  line  will  be  pro- 
jected on  a  true  meridian  to  an  intersection  with  the  north  boundary 
of  the  township  where  a  closing  section  corner  will  be  established 
and  the  distance  measured  to  the  nearest  regular  corner.     The  inter- 
mediate quarter-section  and  section   corners  will  be  established 
alternately  at  regular  intervals  of  40  chains,  counting  from  the  south, 
unless  the  south  boundary  of  the  township  is  itself  defective  in 
alinement.     Where  the  north  boundary  is  not  defective  in  position 
(nor  within  the  danger  zone)  with  reference  to  the  section  corners 
on  the  south  boundaiy  (by  reason  of  the  errors  in  the  alinement  of 
the  east  boundary  being  compensating),  the  first  meridional  section 
line  will  be  projected  5  miles  as  a  true  line  on  a  bearing  calculated  to 
intersect  the  objective  section  corner  on  the  north  boundary,  and  the 
last  mile  will  be  run  as  a  random  line  on  the  same  course  and  cor- 
rected to  a  true  line  after  the  falling  has  been  measured.     The 
remaining  meridional  section  lines  will  be  run  parallel  to  the  one 
first  established,  in  the  usual  manner,  to  closing  section  corners  on 
the  last  mile  or  random  and  true  as  the  case  may  be. 

The  fractional  measurements  of  the  latitudinal  section  lines  in 
the  first  range  of  sections  will  be  placed  in  the  east  half  mile;  else- 
where, unless  the  south  boundary  is  defective  in  alinement,  the 
latitudinal  section  lines  will  be  run  in  the  usual  manner. 

SECTIONAL   CORRECTION    LINE. 

185.  If  the  south  boundary  of  the  township  is  defective  in  aline- 
ment, and  can  not  be  rectified,  and  the  west  boundary  is  thus  made 
defective  in  position,  a  sectional  correction  line  will  be  surveyed 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


Fig.4!. 


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•168  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

as  a  permanent  line  on  a  true  latitudinal  curve  initiated  at  the  first 
regular  section  corner  on  the  east  boundary  and  projected  to  an 
intersection  with  the  west  boundary  of  the  township  where  a  closing 
section  corner  will  be  established  and  the  distance  measured  to  the 
nearest  regular  corner.  The  intermediate  quarter-section  and  sec- 
tion corners  will  be  marked  as  temporary  points  at  regular  intervals 
of  40  chains,  alternately,  counting  from  the  east.  Where  the  west 
boundary  is  not  defective  in  position  (nor  within  the  danger  zone) 
with  reference  to  the  section  corners  on  the  east  boundary  (by  reason 
of  the  errors  in  alinement  of  the  south  boundary  being  compensating) , 
the  first  latitudinal  section  line  will  be  projected  5  miles  as  a  per- 
manent line  on  a  bearing  calculated  to  intersect  the  objective  section 
corner  on  the  west  boundary;  temporary  quarter-section  and  section 
corners  will  be  marked  at  regular  intervals  of  40  chains,  alternately, 
counting  from  the  east. 

The  section  corners  on  the  sectional  correction  line  will  be  estab- 
lished at  the  several  points  of  intersection  of  the  meridional  section 
lines  alined  in  the  normal  manner.  Thereafter  the  quarter-section 
corners  on  the  sectional  correction  line  will  be  established  at  the 
usual  mid-point  positions  except  in  the  east  and  west  ranges  of 
sections.  The  quarter-section  corner  between  sections  25  and  36 
will  be  established  at  40  chains  from  the  west  if  the  east  boundary  is 
defective  in  alinement;  otherwise  it  will  be  fixed  at  the  usual  mid- 
point position.  The  quarter-section  corner  between  sections  30  and 
31  will  be  placed  at  40  chains  from  the  east,  and  if  the  sectional  cor- 
rection line  has  not  been  terminated  at  a  closing  section  corner  on  the 
west  boundary  of  the  township  (as  previously  provided),  the  line 
between  sections  30  and  31  will  be  run  random  and  true  in  the  normal 
manner.  The  quarter-section  corners  on  the  meridional  section 
lines  in  the  south  tier  of  sections  will  be  permanently  established  at 
40  chains  south  from  the  corners  on  the  sectional  correction  line. 
The  balance  of  the  subdivisional  lines  will  be  continued  from  the 
sectional  correction  line  in  the  usual  manner. 

186.  Where  the  south  part  of  the  east  boundary,  or  the  east  part 
of  the  south  boundary,  is  regular,  and  the  balance  of  the  exterior  is 
found  to  be  defective  in  alinement  and  not  subject  to  rectification, 
the  subdivisional  survey  will  be  made  regular  as  far  as  possible. 
The  initial  point  for  the  sectional  guide  meridian,  or  for  the  sectional 
correction  line,  will  be  determined  by  existing  conditions,  and  the 
subdivisional  survey  continued  in  harmony  with  the  principles 


SYSTEM   ©F  RECTANGULAR   SURVEYS. 


169 


Fig.  43. 


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55465°— 19 


170  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

already  outlined.  Thus  the  first  meridional  section  line  would  be 
continued  as  a  sectional  guide  meridian  if  the  north  part  of  the  east 
boundary  is  defective  in  alinement  and  the  north  boundary  is 
thereby  made  defective  in  position,  but  if  the  north  boundary  is  not 
defective  in  position  (nor  within  the  danger  zone)  the  first  meridional 
section  line  should  be  continued  on  a  course  calculated  to  intersect 
the  objective  section  corner  on  the  north  boundary.  The  same  prin- 
ciple would  be  observed  if  the  west  part  of  the  south  boundary  is 
defective  in  alinement  and  the  west  boundary  is  not  defective  in 
position  (nor  within  the  danger  zone),  but  if  the  west  boundary  is 
thus  made  defective  in  position  the  sectional  correction  line  should 
be  established  on  the  true  latitudinal  curve. 

Under  the  provisions  of  the  above  paragraph  it  will  be  seen  that 
the  maximum  number  of  normal  sections  are  to  be  secured  where  the 
condition  of  the  governing  boundaries  warrants  a  combination  of  the 
several  general  plans  of  subdi visional  surveys.  The  sections  adjoin- 
ing the  east  boundary  may  be  considered  regular  to  the  full  extent 
of  their  conformity  with  the  usual  rectangular  limits,  and  where 
such  agreement  obtains  the  quarter-section  corners  on  the  latitudinal 
section  lines  will  be  placed  at  the  normal  mid-point  position.  The 
sections  adjoining  the  south  boundary  of  the  township  can  not  be 
considered  regular  unless  the  meridional  lines  are  established  at  80 
chains  in  length,  and  the  sections  are  otherwise  in  conformity  with 
the  usual  rectangular  limits;  certain  exceptions  to  this  rigid  require- 
ment will  be  noted  under  the  subject  of  " fragmentary  subdivision/* 

187.  The  field  notes  of  subdi  visional  surveys  embracing  either  a 
sectional  guide  meridian,  a  sectional  correction  line,  or  other  gov- 
erning section  line,  will  be  compiled  in  the  same  regular  order 
heretofore  described,  but  appropriate  explanatory  remarks  will  be 
added  indicative  of  the  method  and  order  of  procedure. 

CLOSING   SECTION    LINES. 

188.  In  the  event  of  defective  north  or  west  boundaries,  not  sub- 
ject to  rectification,  where  the  subdi  visional  lines  can  not  be  con- 
nected with  the  previously  established  exterior   section   corners, 
regularly  by  random  and  true  lines  not  exceeding  21/  from  cardinal 
and  at  the  same  time  not  deviating  more  than  21'  from  a  line  parallel 
to  the  opposite  (regular)  boundary  of  the  section,  the  normal  posi- 
tions of  the  randoms  will  be  made  the  true  lines;  a  closing  section 
corner  will  then  be  established  at  the  point  of  intersection  of  the 


SYSTEM  OF  RECTANGULAR   SURVEYS. 


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Port  ofs  bc/y  ffefect-ve  /n 

172  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

section  line  with  the  original  boundary,  and  the  distance  will  be 
measured  to  the  nearest  original  corner.  The  quarter-section  cor- 
ners on  the  closing  section  lines  will  be  placed  uniformly  at  40  chains 
from  the  south  or  east  as  the  case  may  be.  If  not  already  accom- 
plished, the  defective  boundaries  of  the  township  will  be  retraced 
as  may  be  necessary,  and  the  marks  upon  the  original  corners  appro- 
priately altered  as  previously  provided  under  the  subject  of  rectifi- 
cation of  defective  exteriors,  whereupon  new  quarter-section  cor- 
ners, common  to  the  sections  of  the  township  which  is  being  subdi- 
vided, will  be  established  on  the  original  defective  boundaries  at 
the  mean  distance  between  the  closing  section  corners,  or  at  40 
chains  from  one  direction,  depending  upon  the  plan  of  the  subdi- 
vision of  the  section  to  which  a  particular  quarter-section  corner 
belongs. 

189.  Corners  of  two  sections  on  the  governing  south  or  east  boun- 
daries of  a  township  will  not  be  established   as   closing  section 
corners,  but  at  regular  distances  by  measurement  on  said  boundaries 
as  already  provided  under  the  subject  of  rectification  of  defective 
exteriors  before  subdividing;  thereafter  the  position  of  said  corners 
will  control  the  sub  divisional  survey. 

190.  Where  a  section  is  invaded  by  a  State  or  reservation  or  grant 
boundary,  or  by  a  private  claim  of  any  description,  such  as  mineral 
claims,  forest-homestead  claims,  small-holding  claims,  etc.,  whose 
boundaries  are  at  variance  with  the  lines  of  legal  subdivision,  the 
distance  on  the  township  boundary  or  section  line  to  the  point  of 
intersection  with  the  irregular  boundary  will  be  carefully  measured, 
likewise  the  exact  bearing  of  the  irregular  boundary  will  be  deter- 
mined and  the  distance  will  be  measured  to  the  nearest  corner  on 
such  irregular  boundary.    Where  a  private  claim  is  located  entirely 
within  the  limits  of  a  section,  a  connection  will  be  made  from  a 
regular  corner  on  one  of  the  boundaries  of  the  section  to  a  corner  of 
the  claim,  and  the  bearing  and  length  of  the  connecting  line  will  be 
carefully  determined.     In  the  latter  case  a  connecting  traverse  line 
will  be  recorded,  if  one  is  run,  but  it  will  also  be  reduced  to  the 
equivalent  direct  course  and  distance,  all  of  which  will  be  stated  in 
the  field  notes,  and  the  course  and  length  of  the  direct  connecting 
line  will  be  shown  upon  the  plat  of  the  survey. 

191.  If  a  survey  is  to  be  concluded  upon  an  irregular  boundary 
at  variance  with  the  lines  of  legal  subdivision,  or  if  the  survey  is  to 
be  continued  on  a  blank  line  to  acquire  a  definite  location  upon  the 


SYSTEM  OF  RECTANGULAR  SURVEYS.  173 

opposite  irregular  boundary,  but  without  monumenting  the  rec- 
tangular survey  between  such  irregular  boundaries,  a  closing  town- 
ship or  section  corner,  as  the  case  may  be,  will  be  required  at  the 
point  of  intersection  of  the  regular  with  the  irregular  line.  On  the 
other  hand,  if  the  survey  is  not  to  be  so  concluded,  but  is  to  be  con- 
tinued for  the  purpose  of  establishing  a  full  complement  of  section 
and  quarter-section  corners  for  the  control  of  the  subdivision  of  a 
section  so  invaded  by  a  private  claim,  no  closing  corner  will  be 
required. 

192.  In  qvery  case  where  a  closing  township  or  section  corner  is 
to  be  established  upon  a  standard  parallel,  State,  reservation,  grant, 
or  claim  boundary,  or  upon  an  irregular  section  line  or  exterior,  the 
line  closed  upon  (if  the  latter  was  not  established  by  the  surveyor 
who  runs  the  closing  line,  or  if  not  already  retraced  by  him),  will  be 
retraced  between  the  first  corners  to  the  right  and  left  of  the  point 
for  the  closing  corner,  in  order  to  determine  the  exact  alinement  of 
the  line  closed  upon,  to  the  end  that  the  closing  corner  may  be 
established  at  the  precise  point  of  intersection  of  the  two  lines.    The 
distance  from  the  closing  corner  to  the  nearest  corner  on  the  line 
closed  upon  will  always  be  measured  and  recorded. 

SUBDIVISION   OF   SECTIONS. 

193.  The  acts  of  Congress  approved  February  11,  1805,  and  April 
5,  1832,  contain  the  fundamental  provisions  for  the  subdivision  of 
sections  into  quarter  sections  and  quarter-quarter  sections;  the  prin- 
ciples recognized  by  law  have  already  been  stated  in  Chapter  I. 
The  sections  are  not  subdivided  in  the  field  by  the  United  States 
surveyors  unless  provision  therefor  is  specifically  mentioned  in  the 
written  special  instructions,  but  certain  subdivision-of-section  lines 
are  always  protracted  upon  the  official  plats,  and  the  local  surveyor 
who  may  be  employed  by  entrymen  to  run  said  lines  in  the  field  is 
compelled  to  correlate  the  conditions  as  found  upon  the  ground 
with  those  shown  upon  the  approved  plat.    The  United  States  sur- 
veyor is  required  to  so   establish  the  official  monuments  that  a 
proper  foundation  is  laid  for  the  sub  division  of  the  section,  whereby 
the  officially  surveyed  lines  may  be  identified  and  the  subdivision 
of  the  section  controlled  as  contemplated  by  law. 

194.  The  rectangular  system  provides  for  the  unit  of  disposal 
under  the  general  land  laws,  broadly,  the  quarter-quarter  section  of 
40  acres,  upon  a  plan  in  which  the  square  mile,  or  section  of  640 


174  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

acres,  is  the  unit  of  subdivision,  while  the  unit  of  survey  is  the  town- 
ship of  36  sections.  All  agricultural  entries  are  based  upon  descrip- 
tions in  accordance  with  legal  subdivisions  shown  upon  the  offi- 
cial plat.  The  plats  are  constructed  in  harmony  with  the  official 
field  notes  returned  by  the  surveyor.  The  land  included  in  an 
entry  is  identified  on  the  ground  by  fixed  monuments  established 
by  the  surveyor.  A  United  States  land  patent  grants  to  the  entry- 
man  a  title  of  ownership  to  a  tract  defined  by  certain  fixed  monu- 
ments on  the  ground  and  related  by  description  and  outline  to  the 
official  plat.  The  function  of  the  United  States  surveyor  has  been 
fulfilled  when  he  has  properly  executed  and  monumented  his  survey 
and  returned  an  official  record  thereof  in  the  shape  of  complete 
detailed  field  notes  and  a  plat.  The  function  of  the  local  surveyor 
begins  when  he  is  employed  as  an  expert  to  identify  the  lands  which 
have  passed  into  private  ownership;  this  may  be  a  simple  or  a  most 
complex  problem,  depending  largely  upon  the  condition  of  the 
original  monuments  as  affected  principally  by  the  lapse  of  time  since 
the  execution  of  the  official  survey.  The  work  of  the  local  surveyor 
usually  includes  the  subdivision  of  the  section,  already  mentioned 
as  the  official  unit  of  subdivision,  into  the  fractional  parts  shown 
upon  the  approved  plat.  In  this  capacity  the  local  surveyor  is  per- 
forming a  function  contemplated  by  law,  and  he  can  not  properly 
Berve  his  client  or  the  public  unless  he  is  familiar  with  the  legal 
requirements  concerning  the  subdivision  of  sections.  In  the  event 
that  the  original  monuments  have  become  lost  the  surveyor  can 
not  hope  effectively  to  recover  said  corners  without  a  full  under- 
standing of  the  record  concerning  their  original  establishment,  nor 
can  the  surveyor  hope  legally  to  restore  the  same  until  he  has 
mastered  not  only  the  principles  observed  in  the  execution  of  the 
original  survey,  but  the  principles  upon  which  the  courts  having 
jurisdiction  over  such  matters  have  based  their  rulings. 

195.  The  General  Land  Office  assumes  no  control  or  direction 
.over  the  acts  of  local  and  county  surveyors  in  the  matters  of  sub- 
, division  of  sections  and  reestablishment  of  lost  corners  of  original 
•surveys  where  the  lands  have  passed  into  private  ownership, 
nor  will  it  issue  instructions  in  such  cases.  It  follows  the 
general  rule  that  disputes,  arising  from  uncertain  or  erroneous  loca- 
tion of  corners,  originally  established  by  the  United  States,  are  to 
be  settled  by  the  proper  local  authorities  or  by  amicable  adjustment, 
and  the  office  desires  that  the  rules  controlling  the  acts  of  its  own 
surveying  service  be  considered  by  all  other  surveyors  as  merely 


SYSTEM   OF  RECTANGULAR  SURVEYS.  175 

advisory  and  explanatory  of  the  principles  which  should  prevail  in 
performing  such  duties. 

The  subject  of  restoration  of  lost  corners  will  be  treated  in  a 
later  chapter,  as  the  purpose  here  is  to  outline  the  principles  con- 
cerning the  subdivision  of  sections,  which  will  be  recognized  alike 
by  the  General  Land  Office  surveying  service  and  by  all  local  sur- 
veyors. 

SUBDIVISION   BY   PROTRACTION. 

196.  Upon  the  plat  of  all  regular  sections  the  boundaries  of  the 
quarter  sections  are  shown  by  broken  straight  lines  connecting  the 
opposite  quarter-section  corners.  The  sections  bordering  the  north 
and  west  boundaries  of  a  normal  township,  excepting  section  6, 
are  further  subdivided  by  protraction  into  parts  containing  two  regu- 
lar half -quarter  sections  and  four  lots,  the  latter  containing  the  frac- 
tional areas  resulting  from  the  plan  of  subdivision  of  normal  town- 
ships; the  lines  of  the  half-quarter  sections  are  protracted  from  three 
points  20  chains  distant  from  the  line  connecting  the  opposite 
quarter  section  corners,  two  of  s$id  distances  counting  on  the  oppo- 
site section  lines  and  one  counting  on  the  line  between  the  fractional 
quarter  sections;  the  lines  subdividing  the  fractional  half-quarter 
sections  into  the  fractional  lots  are  protracted  from  mid-points  on 
the  opposite  boundaries  of  the  fractional  quarter  section.  The  two 
interior  sixteenth-section  corners  on  the  boundaries  of  the  fractional 
northwest  quarter  of  section  6  are  similarly  fixed  at  points  20  chains 
distant  north  and  west  from  the  center  of  the  section,  from  which 
points  lines  are  protracted  to  corresponding  points  on  the  west  and 
north  boundaries  of  the  section,  resulting  in  subdivisions  containing 
one  regular  quarter-quarter  section  and  three  fractional  lots.  The 
fractional  lots  herein  described  will  be  numbered  yi  a  regular  series 
progressively  from  east  to  west  or  from  north  to  south,  in  each  sec- 
tion. As  section  6  borders  on  both  the  north  and  west  boundaries 
of  the  township,  the  fractional  lots  in  the  same  will  be  numbered 
commencing  with  No.  1  in  the  northeast,  thence  progressively  west 
to  No.  4  in  the  northwest,  and  south  to  No.  7  in  the  southwest  frac- 
tional quarter-quarter  section. 

Entrymen  are  allowed,  under  the  law,  to  acquire  title  to  any 
regular  quarter-quarter  section,  but  as  such  subdivisions  are  aliquot 
parts  of  quarter  sections  based  upon  mid-point  protraction,  it  is  not 
deemed  necessary  to  indicate  these  lines  upon  the  official  plat. 


176 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


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Showing  areas.  Showing  calculated  distances. 

Examples  of  subdivision  by  protraction. 


SYSTEM  OF  RECTANGULAR  SURVEYS. 

fig.48. 


177 


Meanderable  River. 


Meanderable  Lake. 


Mineral  Claims. 


E.bdy. defective  in  alinement. 


S.bdy.  defective  in  alinement..  .E&S.bdrs. defective  in  alinement. 

Examples  of  subdivision  of  fractional  sections. 


178  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

197.  Sections  which  are  invaded  by  meanderable  bodies  of  water, 
or  by  approved  claims  at  variance  with  the  regular  legal  subdivisions, 
are  subdivided  by  protraction  into  regular  and  fractional  parts  as 
may  be  necessary  to  form  a  suitable  basis  for  the  entry  of  the  public 
lands  remaining  undisposed  of,  and  to  describe  the  latter  separately 
a(nd  apart  from  the  segregated  areas. 

The  meander  line  of  a  .body  of  water  and  the  boundary  lines  of 
private  claims  are  platted  in  accordance  with  lines  run  or  connec- 
tions made  in  the  field;  thereupon  the  sections  so  invaded  are  sub- 
divided as  nearly  as  possible  in  conformity  with  the  uniform  plan 
already  outlined.  The  subdivision-of -section  lines  are  terminated 
at  the  meander  line  or  claim  boundary,  as  the  case  may  be,  but  the 
position  of  the  subdivision-of -section  lines  is  controlled  precisely 
as  though  the  section  had  been  completed  regularly.  In  the  case 
of  a  section  whose  boundary  lines  are  in  part  within  the  limits  of  a 
meanderable  body  of  water,  or  within  the  boundaries  of  a  private 
claim,  the  said  fractional  section  lines  are,  for  the  purpose  of 
uniformity,  completed  in  theory,  and  the  protracted  position  of 
the  subdivision-of-section  lines  is  controlled  by  the  theoretical 
points  so  determined. 

198.  In  the  subdivision  of  fractional  sections  as  many  regular 
parts  should  be  .secured  as  possible,  except  to  avoid  thus  creating 
poorly  shaped  fractional  lots.     Skill  and  judgment  must  be  exercised 
to  accomplish  a  subdivision  which  embraces  simplicity  of  platting 
as  well  as  a  form  to  each  and  every  lot  that  will  prove  to  be  equitable 
to  the  entryman.     In  the  case  of  fractional  lots  along' the  north  and 
west  boundaries  of  a  township,  and  in  other  similar  cases  where  a 
lot  has  a  full  normal  width  of  20  chains  in  one  direction,  it  is  gen- 
erally advisable  to  avoid  areas  of  less  than  10  or  more  than  50  acres, 
but  in  the  instance  of  fractional  lots  along  a  meander  line  or  other 
irregular  broken  boundary,  where  the  width  of  the  lot  in  both  direc- 
tions may  be  considerably  less  than  20  chains,  resulting  in  tracts  of 
more  compact  form,  it  is  generally  better  to  avoid  an  area  of  less 
than  5  or  more  than  45  acres.    The  purpose  of  the  aforestated  limits 
is  to  create  fractional  lots  of  dimensions  that  will  facilitate  all  entries 
being  made  in  a  form  that  is  optional  with  the  entryman;  an  ad- 
herence to  this  practice  will  greatly  reduce  the  necessity  for  the  con- 
struction of  supplemental  plats  now  frequently  demanded  for  no 
other  purpose .     Extreme  lengths  or  narrow  widths  should  be  avoided ; 
the  longer  direction  should  extend  back  from  a  meander  line  or 


SYSTEM  OF  RECTANGULAR  SURVEYS.  179 

claim  boundary  rather  than  along  the  same.  It  is  inconsistent  that 
a  fractional  lot  lie  partly  in  two  sections^  and  it  is  generally  better, 
when  consistent  with  other  rules,  to  avoid  fractional  lots  extending 
from  one  into  another  fractional  quarter  section. 

199.  To  secure  a  uniform  system  for  numbering  lots  of  fractional 
sections,   including  those   above   specified,   imagine   the   section 
divided  by  parallel  latitudinal  lines  into  tiers,  numbered  from 
north  to  south;  then,  beginning  with  the  eastern  lot  of  the  north 
tier,  call  it  No.  1,  and  continue  the  numbering  west  through  the 
tier,  then  east  in  the  second,  west  in  the  third,  east  in  the  fourth 
tier,  etc.,  until  all  fractional  lots  have  been  numbered.    A  lot  ex- 
tending north  and  south  through  two,  or  part  of  two  tiers,  will  be 
numbered  in  the  tier  containing  its  greater  area.     In  case  any  tier  is 
without  numbered  lots,  the  numbering  will  be  continued  in  the 
next  tier  to  the  south.     This  method  of  numbering  will  apply  to 
any  part  of  a  section.    A  section  that  has  been  partly  surveyed  at 
different  times  should  have  no  duplication  of  lot  numbers. 

200.  When,  by  reason  of  irregular  surveys  or  from  other  causes, 
the  length  of  a  township  from  south  to  north  exceeds  the  regular 
length  of  480  chains,  or  the  width  from  east  to  west  exceeds  480 
chains,  to  such  an  extent  as  to  require  two  or  more  tiers  of  lots  along 
the  north  boundary,  or  two  or  more  ranges  of  lots  along  the  west 
boundary,  as  the  case  may  be,  the  entire  north  or  west  portions  of 
said  sections  beyond  the  regular  legal  subdivisions  usually  provided 
in  these  sections,  will  be  suitably  lotted,  and  to  each  lot  will  be 
assigned  a  proper  number.     Certain  exceptions  to  this  rule  will  be 
found  in  Chapter  VII,  in  the  instance  of  townships  which  possess 
abnormal  dimensions  in  one  or  both  directions. 

201.  If  the  first  meridional  section  line  of  a  township  has  been 
established  as  a  sectional  guide  meridian,  or  the  first  latitudinal 
section  line  has  been  established  as  a  sectional  correction  line, 
fractional  lots  will  result  along  the  east  or  south  boundary  of  the 
township,   as  existing  conditions  may  necessitate.    Thus,   where 
either  the  east  or  south  boundaries  of  a  township  are  defective  in 
alinement  (and  not  subject  to  rectification  before  subdividing)  the 
sections  bordering  such  defective  boundaries  will  be  subdivided  by 
protraction  in  accordance  with  rules  similar  to  those  which  operate 
in  regard  to  sections  bordering  the  north  and  west  boundaries  of  a 
normal  township.    Other  examples  of  subdivision  of  sections  will  be 
found  under  the  general  subject  of  "fragmentary  subdivision." 


180  .MANUAL  OF  SURVEYING  INSTRUCTIONS. 

SUBDIVISION    BY    SURVEY. 

202.  The  rules  for  subdivision  of  sections  by  actual  survey  in  the 
field  are  based  upon  the  laws  governing  the  survey  of  the  public  lands. 
When  cases  arise  which  are  not  covered  by  these  rules,  and  the 
advice  of  the  General  Land  Office  in  the  matter  is  desired,  the  letter 
of  inquiry  should,  in  every  instance,  contain  a  description  of  the 
particular  tract  or  corner,  with  reference  to  township,  range  and 
section  of  the  public  surveys,  to  enable  the  office  to  consult  the 
record;  also  a  diagram  showing  conditions  found,  giving  distances 
in  chains  and  links  and  not  in  feet. 

203.  Preliminary  to  subdivision  it  is  essential  to  know  the  actual 
boundaries  of  the  section,  as  it  can  not  be  subdivided  legally  until 
the  section  corners  and  quarter-section  corners  have  either  been 
found  or  restored  by  proper  methods,  and  the  resulting  courses  and 
distances  determined  by  survey.     The  practice  of  entering  a  section 
to  survey  a  tract  from  only  one  or  two  corners,  and  those  perhaps 
unreliable,  is  unlawful. 

204.  The  order  of  procedure  is:  First,  identify  or  reestablish  the 
boundaiy  corners;  next,  fix  the  lines  of  quarter  sections;  then,  form 
smaller  tracts  by  equitable  and  proportionate  division,  according 
to  the  following  rules: 

205.  Subdivision    of  sections   into    quarter  sections. — Under  the 
provisions  of  the  act  of  Congress  approved  February  11,  1805,  the 
course  to  be  pursued  in  the  subdivision  of  sections  into  quarter  sec- 
tions is  to  run  straight  lines  from  the  established  official  quarter- 
section  corners  to  the  opposite  corresponding  corners.     The  point  of 
intersection  of  the  lines  thus  run  will  be  the  corner  common  to  the 
several  quarter  sections,  or,  in  other  words,  the  legal  center  of  the 
section. 

Upon  the  lines  closing  on  the  north  and  west  boundaries  of  a 
regular  township  the  quarter-section  corners  are  established  by  the 
United  States  surveyors  at  40  chains  to  the  north  or  west  of  the  last 
interior  section  corners,  and  the  excess  or  deficiency  in  the  measure- 
ment is  thrown  into  the  half  mile  next  to  the  township  or  range  line, 
as  the  case  may  be. 

Where  there  are  double  sets  of  section  corners  on  township  and 
range  lines  the  quarter-section  corners  for  the  sections  south  of  the 
township  lines  and  east  of  the  range  lines  have  not  always  been 
established  in  the  field  by  the  United  States  surveyors,  but  in  sub- 
dividing such  sections  said  quarter-section  corners  should  be  so 


SYSTEM  OF  RECTANGULAR  SURVEYS.  181 

placed  as  to  suit  the  calculations  of  the  areas  of  the  quarter  sections 
adjoining  the  township  boundaries  as  expressed  upon  the  official 
plat,  adopting  proportionate  measurements  where  the  new  measure- 
ments of  the  north  or  west  boundaries  of  the  section  differ  from  the 
original  measurements. 

206.  Subdivision  of  fractional  sections. — The  law  provides  that 
where  opposite  corresponding  quarter-section  corners  have  not  been 
or  can  not  be  fixed,  the  sub division-of -section  lines  should  be  ascer- 
tained by  running  from  the  established  corners  north,  south,  east 
or  west  lines,  as  the  case  may  be,  to  the  water  course,  reservation 
line,  or  other  boundaiy  of  such  fractional  section,  as  represented 
upon  the  official  plat.     In  this  the  law  presumes  the  section  lines 
surveyed  and  marked  in  the  field  by  the  United  States  surveyors  to 
be  due  north  and  south  or  east  and  west  lines,  but  this  is  not  usually 
the  case.    Hence,  in  order  to  carry  out  the  spirit  of  the  law,  it  will 
be  necessary  in  running  the  sub  divisional  lines  through  fractional 
sections  to  adopt  mean  courses,  where  the  section  lines  are  not  due 
lines,  or  to  run  the  sub  division-of -section  lines  parallel  to  the  east, 
south,  west  or  north  boundary  of  the  section,  as   conditions  may 
require,  where  there  is  no  opposite  section  line.     (See  sec.  197.) 

207.  Subdivision  of  quarter  sections  into  quarter-quarter  sections. — 
Preliminary  to  the  subdivision  of  quarter  sections,  the  quarter- 
quarter-  or  sixteenth-section  corners  will  be  established  at  points 
midway   between   the   section  and    quarter- section    corners,   and 
between  the  quarter-section  comers  and  the  center  of  the  sec- 
tion, except  on  the  last  half  mile  of  the  lines  closing  on  irregular 
boundaries,  where  they  should  be  placed  at  20  chains,  proportionate 
measurement,  counting  from  the  regular  quarter-section  corner. 

The  quarter-quarter-  or  sixteenth-section  corner^  having  been 
established  as  directed  above,  the  center  lines  of  the  quarter  section 
will  be  run  straight  between  opposite  corresponding  quarter-quarter- 
or  sixteenth-section  corners  on  the  quarter-section  boundaries.  The 
intersection  of  the  lines  thus  run  will  determine  the  legal  center  of  a 
quarter  section. 

208.  Subdivision  of  fractional  quarter  sections. — The  subdi  visional 
lines  of  fractional  quarter  sections  will  be  run  from  properly  estab- 
lished quarter-quarter-  or  sixteenth-section  corners,  with  courses  gov- 
erned by  the  conditions  represented  upon  the  official  plat,  to  the 
lake,  water-course  or  reservation  which   renders  such  tracts  frac- 
tional.    (See  sec.  197.) 


182  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

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Official  measurements. 


Remeasurements. 


SYSTEM  OF  RECTANGULAR  SURVEYS.  183 

209.  By  "  proportionate  measurement "  is  meant  a  measurement 
having  the  same  ratio  to  that  recorded  in  the  original  field  notes  as 
the  length  of  the  line  by  re-measurement  bears  to  its  length  as  given 
in  the  record.    Reasonable  discrepancies  between  former  and  new 
measurements  may  generally  be  expected .    Errors  may  occur  through 
many  causes  and  should  be  as  carefully  avoided  in  re-measuremente 
as  in  original  surveys.    Instead  of  the  old  practice  of  "adjusting 
the  chain'*  to  suit  the  former  measure,  the  distance  obtained  by 
a  precise  method  is  compared  with  that  of  the  record,  and  the 
shortage  or  surplus  is  computed  by  proportion,  producing  the  same 
result  in  a  more  reliable  manner.    For  example:  The  length  of  the 
line  from  the  quarter-section  corner  on  the  west  boundary  of  section 
2  to  the  north  line  of  the  township,  by  the  United  States  surveyor's 
measurement  was  reported  as  43.40  chains,  and  by  the  county  sur- 
veyor's measurement  was  found  to  be  42.90  chains;  then  the  distance 
which  the  quarter-quarter-  or  sixteenth-section  corner  should  be 
located  north  of  the  quarter-section  corner  would  be  determined  by 
proportion  as  follows:  As  43.40  chains,  the  official  measurement  of 
the  whole  distance,  is  to  42.90  chains,  the  county  surveyor's  measure- 
ment of  the  same  distance,  so  is  20  chains,  original  measurement,  to 
19.77  chains  by  the  county  surveyor's  measurement,  showing  that 
by  proportionate  measurement  in  this  case  the  quarter-quarter-  or 
sixteenth-section  corner  should  be  set  at  19.77  chains  north  of  the 
quarter-section  corner,  instead  of  20  chains  north  of  said  corner,  as 
represented  on  the  official  plat.     In  this  manner  the  discrepancies 
between  original  and  new  measurements  are  equitably  distributed. 

210.  By  way  of  recapitulation  it  should  be  emphasized  that  when 
entrymen  have  acquired  title  to  certain  legal  subdivisions  they  have 
become  the  owners  of  the  identical  ground  area  represented  by  the 
same  subdivisions  upon  the  official  plat.     It  is  a  matter  of  expert  or 
technical  procedure  to  mark  out  the  legal  subdivisions  called  for  in 
a  patent,  and  entrymen  are  advised  that  a  competent  surveyor 
should  be  employed.    The  surveyor  must  necessarily  identify  the 
section  boundaries  and  locate  the  legal  center  of  the  section  in  order  to 
determine  the  boundaries  of  a  quarter  section.     Then,  if  the  boun- 
daries of  quarter-quarter  sections,  or  fractional  lots,  are  to  be  deter- 
mined on  the  ground,  the  boundaries  of  the  quarter  section  must  be 
measured,  and  the  sixteenth-section  corners  thereon  should  be  fixed 
in  accordance  with  the  proportional  distances  represented  upon  the 
approved  plat,  thereupon  the  legal  center  of  the  quarter  section 


184  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

may  be  duly  located.  Thus  will  be  produced  in  the  field  the  figure 
represented  upon  the  plat,  every  part  of  the  former  in  true  propor- 
tion to  the  latter,  where  the  elements  of  absolute  distance  and  area 
have  given  away  to  corresponding  proportional  units  as  defined  by 
fixed  monuments  established  in  the  original  survey. 

FRAGMENTARY   SUBDIVISION  OF  TOWNSHIPS. 

211.  In  the  preceding  articles  covering  the  subject  of  subdivision 
of  townships  every  assumption  was  based  upon  initiating  the  sub- 
divisional  survey  upon  regularly  established  exteriors,  or,  when 
necessary,  a  sectional  guide  meridian  or  a  sectional  correction  line, 
or  both,  were  to  be  established,  upon  which  rested  the  control  of 
the  subdivision  of  the  township.    The  subdivision  of  every  full 
township  may  always  be  governed  by  the  aforestated  rules,  but  many 
other  factors  operate  in  determining  the  method  and  order  of  pro- 
cedure to  be  adopted  in  the  instance  of  fractional  townships  which 
have  no  linear  south  or  east  boundary,  or  in  the  case  of  continuing 
with  the  survey  of  partially  subdivided  townships,  where  one  or  more 
of  the  previously  established  section  lines  may  be  found  to  be  de- 
fective in  respect  to  the  rectangular  limit,  or  where  partially  sur- 
veyed sections,  or  sections  containing  outlying  areas  protracted  as 
surveyed,  are  to  be  completed.    The  surveyor  can  not  hope  to 
master  the  subject  of  fragmentary  subdivision  of  townships  until 
he  has  become  thoroughly  familiar  with  every  question  relating  to 
the  subdivision  of  sections,  nor  is  it  possible  to  give  in  the  Manual 
an  example  of  every  intricate  problem  which  may  be  encountered 
in  the  field;  thus  the  following  discussion  deals  primarily  with  the 
principles,  which  must  be  considered  in  the  field,  operating  to 
control  the  surveyor's  method  and  order  of  procedure.     It  is  possible, 
however,  that  cases  may  arise  so  complex  in  their  character  as  to 
produce  a  feeling  of  doubt  relative  to  the  proper  solution  of  the  prob- 
lem; in  which  case  the  surveyor  will  at  once  communicate  with  the 
proper  supervising  officer,  submitting  information,  by  letter  and 
diagram,  of  the  exact  condition  as  found  by  him,  and  the  necessary 
instructions  will  be  forwarded  as  soon  as  practicable. 

FRACTIONAL  TOWNSHIPS. 

212.  Where  by  reason  of  the  presence  of  a  large  meanderable 
body  of  water,  impassable  objects,  a  State  or  reservation  or  grant 
boundary,  or  for  other  similar  reasons  a  township  is  made  fractional 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


185 


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186  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

and  is  without  a  full  linear  south  or  east  boundary,  and  it  has  been 
found  advisable  to  run  section  lines  as  offsets  to  the  township  ex- 
teriors, the  fractional  section  lines  south  and  east  of  said  controlling 
lines  will  be  projected  opposite  to  the  usual  direction;  the  fractional 
measurements  on  said  lines  and  the  resulting  fractional  lots  will  be 
placed  against  the  irregular  boundary.  If  similar  conditions  obtain 
throughout  the  north  or  west  part  of  a  fractional  township  no  depart- 
ure from  the  regular  order  of  subdivision  becomes  necessary;  in  all 
such  cases  the  fractional  measurements  on  the  exterior  and  subdi- 
visional  lines,  and  the  resulting  fractional  lots,  will  be  placed  to  the 
north  and  west  against  the  irregular  boundary. 

213.  Where  on  account  of  impassable  objects  or  for  other  reasons 
no  part  of  the  south  boundary  of  a  township  can  be  regularly 
established,  the  subdivision  thereof  may  proceed  from  north  to 
south  and  from  east  to  west,  thereby  throwing  all  fractional  meas- 
urements and  areas  against  the  west  boundary  and  the  meanderable 
stream  or  other  boundary  limiting  the  township  on  the  south;  if  the 
east  boundary  is  without  regular  section  corners  and  the  north 
boundary   has  been   run   eastwardly  as  a  true  line,  with  section 
corners  at  regular  intervals  of  80  chains,  the  subdivision  of  the 
township  may  be  made  from  west  to  east,  in  which  case  the  frac- 
tional measurements  and  areas  will  be  thrown  against  the  irregular 
east  boundary;  on  the  other  hand,  if  the  north  boundary  of  section  6 
is  fractional,  a  sectional  guide  meridian  will  be  initiated  at  the 
easternmost  regular  section  corner  on  the  north  boundary  of  the 
township,  which  will  be  projected  to  the  south  to  take  the  place  of 
a  governing  east  boundary,  thus  the  subdi visional  survey  would  be 
projected  from  north  to  south  and  from  east  to  west,  with  fractional 
measurements,  and  resulting  fractional  lots,  on  the  east,  south  and 
west  boundaries  of  the  township.     The  accompanying  diagrams  are 
illustrative  of  the  principles  which  operate  to  control  the  subdivi- 
sion of  partial  townships. 

214.  A  very  considerable  class  of  surveys  now  coming  before  the 
General  Land  Office  embraces  the  continuation  of  the  subdivisional 
survey  of  townships  previously  subdivided  in  part  only,  frequently 
including  the  completion  of  partially  surveyed  sections  or  of  sec- 
tions containing  outlying  areas  protracted  as  surveyed.     If  defective 
conditions  are  encountered  in  the  previously  established  surveys, 
the  problems  concerning  the  procedure  to  be  adopted  multiply 
rapidly  and  require  the  greatest  skill  on  the  part  of  the  surveyor. 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


187 


Fig.  52. 


±J±3 

.  -t  _|_  L_ 

"1 

t 

1 
I 

i 
I 

1 
I 

I 
1 

•-  1 

±7-- 

I 

I 

-"1 

i 

I 

I 

i 
•~l 
--T30-- 

-H 
j 

Auxrlier, 

,,„., 

1 

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i     i/ 

rx" 

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1 

36 

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-4 

Subdivide  Regularly. 

Fig.  53. 


188  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

In  the  construction  of  new  township  plats  the  former  practice  of 
showing  certain  outlying  areas  of  sections  protracted  as  surveyed 
lias  been  abandoned  as  unsatisfactory  and  inconsistent  with  the 
surveying  laws. 

RETRACEMENTS. 

215.  Practically  all  fragmentary  surveys  require  more  or  less  re- 
tracement  of  the  original  surveys  in  order  to  identify  the  initial  and 
closing  lines;  such  retracements  will  always  be  accompanied  by  the 
restoration  of  all  lost  corners  adjacent  to  the  sections  embracing,  in 
whole  or  in  part,  the  areas  to  be  included  in  the  extension  survey, 
in-so-far  as  the  section  or  subdivision -of -section  lines  controlling  the 
new  areas  may  depend  upon  the  position  of  the  previously  estab- 
lished corners.  The  surveyor  will  often  be  required,  in  order  to  de- 
termine properly  the  position  of  a  lost  corner,  to  retrace  additional 
lines  which  are  not  the  boundaries  of  sections  containing  the  new 
areas  to  be  surveyed,  but  no  reestablishments  on  such  lines  are  re- 
quired. The  theoretical  position  of  a  lost  corner  may  be  at  variance 
with  an  unofficial  corner  established  by  local  survey,  accepted  and 
recognized  by  the  owners  of  the  private  lands  affected ;  thus  much 
trouble  between  landowners  is  avoided  if  the  reestablishments  are 
confined  strictly  to  those  corners  which  control  the  position  of  the 
section  boundaries  or  the  subdivision-of-section  lines  affecting  the 
public  lands  to  be  surveyed.  A  general  exception  to  the  foregoing 
rule  will  be  made  in  the  case  of  identified  original  corners  which 
are  adopted  as  a  basis  from  which  to  control  the  reestablishments 
bordering  the  public  land  sections;  such  original  corners,  if  not  in  a 
good  state  of  preservation,  will  be  reconstructed  in  first-class  order, 
a  complete  record  of  which  will  be  embodied  in  the  field  notes.  All 
restorations  of  lost  corners  will  be  made  in  strict  accordance  with 
the  provisions  of  Chapter  V  of  the  Manual.  In  the  instance  of  de- 
fective conditions  contained  in  the  previously  established  lines,  ex- 
ceeding the  rectangular  limit,  even  though  all  original  corners  may 
be  fully  identified  and  in  a  good  state  of  preservation,  the  necessary 
retracements  of  the  section  boundaries  will  be  made  in  order  to  de- 
termine the  factors  entering  into  the  closing  error  and  to  furnish 
suitable  data  for  the  calculation  of  the  areas  of  the  resulting  fractional 
lots  embraced  in  the  extension  survey. 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


189 


Fig.  54. 


30.00 

— 

—  T  

r~ 

6 

5 

4 

--3  — 

L_ 

1 

! 
f" 

7 

8 

9 

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t 
ITS 

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1    I     t 

1      !      1 
!      t      1 

i     t     \ 
<     \     I 

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18  17  16  15 

Subdivide  from  north  to  south,  and 
from  west  to  east. 


Froc. 


14 


Subdivide  from  north  to  south, 
and  from  east  to  west. 


190  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

COMPLETION   OF  PARTIALLY   SURVEYED   SECTIONS. 

216.  Many  assignments  for  fragmentary  surveys  require  the  com- 
pletion of  the  survey  of  portions  of  boundaries  of  sections  heretofore 
unsurveyed,  in  which  sections  are  contained  areas  fixed  in  position 
by  less  than  the  regular  complement  of  corners  usually  established 
for  the  identification  of  the  legal  subdivisions  of  the  section.  In 
the  completion  of  such  partially  surveyed  sections,  the  surveyor 
will  be  expected  to  give  full  consideration  to  the  manner  of  pro- 
tecting acquired  rights  based  upon  the  former  approved  plats. 

The  following  ten  principles  are  distinctly  applicable  to  the  sub- 
ject: 

1st.  The  legal  procedure  governing  the  subdivision  of  any 
normal  section  into  quarter  sections  is  based  broadly  on  the 
principle  that  the  partition  lines  may  be  definitely  fixed  bv 
four  opposite  quarter-section  corners  established  on  its  bound- 
aries; the  intersection  of  the  true  center  lines  thus  controlled 
is  .the  legal  point  for  the  interior  quarter-section  corner  of  a 
section. 

2d.  The  legal  procedure  governing  the  subdivision  of  regular 
quarter  sections  into  quarter-quarter  sections  is  based  broadly 
on  the  same  principle  of  controlling  lines  projected  between 
opposite  sixteenth-section  corners  of  the  quarter  section,  the 
latter  corners  established  at  mid-points  on  the  true  lines  bound- 
ing the  quarter  section;  the  intersection  of  the  true  center 
lines  of  the  quarter  section  is  the  legal  point  for  the  interior 
sixteenth-section  corner  of  such  regular  quarter  section. 

3d.  The  legal  procedure  governing  the  subdivision  of  sections 
containing  fractional  lots  into  their  component  regular  quarter- 
quarter  sections  and  fractional  lots  is  based  on  the  same  principle 
with  the  simple  modification  that  the  sixteenth-section  corners 
on  the  boundaries  of  such  quarter  sections  are  themselves 
established  at  distances  conformable  to  the  proportions  shown 
on  the  official  plat. 

4th.  The  fact  that  the  full  complement  of  four  section  corners 
of  the  section  and  all  of  the  four  opposite  quarter-section  corners 
has  not  been  established  in  an  accepted  survey  does  not  impair 
the  validity  of  any  areas  shown  upon  the  approved  plat,  and 
the  legal  procedure  to  be  adopted  in  the  extension  of  the  bound- 
aries of  such  sections  must  be  such  as  to  fix,  within  reasonable 
limits,  the  remaining  (quarter-section  corners  in  a  position 
which  will  protect  the  integrity  of  the  original  areas  by  con- 
trolling center  lines  connecting  the  old  and  new  quarter-section 
corners. 

5th.  In  the  rectangular  system  the  section  is  recognized  as 
the  unit  of  subdivision,  and  in  proceeding  with  the  extension 
of  fragmentary  surveys  first  consideration  must  necessarily  be 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


191 


Fig. 56. 

Parallel  to  S.  bdy. 


.  Mid-poin1 

1 

80 

80 

o 

1  ' 

\ 
\ 
\ 
} 

2 

1      *  1 

f 

~^^§, 

I  • 

\ 
\ 

-  1 

\ 

& 

Shown  0s 

~     r 

regular. 

I        7 

\ 

8      | 

\ 

(^ 

Para/tel  fo  S.  bdy. 


Mid-p 

f          80 

oirit 
80 

1  —  —  
\ 

-v                                 I 

o 

1    ! 

2 

3                      4        ,g 

. 

<~~s^^ 

I  6 

•  | 

^          $h  o  wn  os 

^^ 

regu/ar. 

Q            _ 
Q             / 

a 

East  boundary  of  section  out  of  limits  in  measurement;  southeast  quarter  protracted 
as  surveyed;  and  section  to  be  completed 


192  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

given  to  the  completion  of  the  survey  of  fractional  sections. 
No  invasion  of  the  original  unit  is  tolerable  if  any  portion  of 
such  unit  has  been  surveyed,  or  if  outlying  areas  have  been 
shown  protracted  as  surveyed. 

6th.  "Reasonable  limits"  for  the  fixation  of  ^  the  remaining 
quarter-section  corners  of  a  section  in  a  position  which  will 

rtect  the  integrity  of  the  original  areas  of  such  section  may 
considered  such  as  for  alinement  when  not  to  exceed  21' 
from  a  cardinal  course,  and  for  measurement  when  not  to  exceed 
25  links  from  40  chains  where  the  opposite  portion  of  the  section 
boundary  is  shown  as  40  chains,  or  in  proportion  as  a  limiting 
difference  when  the  opposite  portion  of  the  section^is  more  or 
less  than  40  chains.  This  concession  as  to  limits  is  made  in 
the  interest  of  simplicity,  where  by  such  concession  rectangu- 
larity  of  both  the  old  and  new  surveys  may  be  maintained  if 
so  harmonized. 

7th.  The  position  of  the  new  quarter-section  corner  which  is 
to  be  established  on  the  new  opposite  boundary  of  a  fractional 
section  will  be  controlled  from  one  direction  only  if  the  old 
opposite  distance  has  been  made  to  count  from  one  direction 
only,  and  the  controlling  measurement  will  be  made  to  harmo- 
nize with  the  length  of  the  opposite  portion  of  the  section,  but 
if  the  old  opposite  distance  has  been  made  to  count  from  two 
directions  the  position  of  the  new  quarter-section  corner  will 
be  controlled  from  the  two  directions  and  the  proportional 
lengths  of  the  two  portions  of  the  new  line  will  be  made  to 
harmonize  with  the  proportional  lengths  of  the  two  parts  of 
the  old  opposite  boundary,  all  as  indicated  by  the  distances 
and  areas  shown  on  the  original  approved  plat. 

8th.  The  underlying  principles  governing  the  rectangular 
surveying  system  are  equally  applicable  to  the  completion  of 
the  survey  of  fractional  sections,  and  given  a  condition  in  an 
original  survey  which  in  all  its  various  elements  is  "  within 
limits''  within  the  meaning  of  the  rectangular  surveys,  the 
simple  plan  of  continuing  in  the  same  manner  and  order  as 
would  have  been  adopted  in  the  original  survey,  if  the  same 
had  not  been  discontinued,  will  accomplish  usually  in  its 
simplest  form  the  completion  of  the  survey  of  fractional  sections; 
this  becomes  the  first  duty  of  the  surveyor  before  proceeding 
with  the  survey  of  additional  sections,  so  tnat  should  irregularity 
be  developed,  no  invasion  of  partially  surveyed  sections  can 
result  from  the  irregularities  of  other  sections.  It  follows  in 
principle,  when  irregularity  is  developed,  that  the  surveyor 
will  be  best  prepared  to  determine  the  proper  method  of  survey 
adapted  to  procure  simplicity  of  correction  of  existing  irregu- 
larities and  an  early  resumption  of  regularity,  when  he  is  in 
possession  of  full  data  concerning  the  conditions  of  all  the  old 
lines  limiting  the  fragmentary  surveys  and  upon  which  the 
new  lines  are  to  be  initiated  or  closed,  his  knowledge  being 
based  upon  the  results  of  actual  retracement  of  such  irregular 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


193 


Fig.  57. 

Ron dom  and  true. 


(20JOO) 

(Froc.) 

(20.OO) 

(20.00) 

3 

2 

\ 

§       80 

J 

' 

- 

4 

5 

6 

'  I 

1  - 

^         Shown  as 
regular. 

8  1 

(20.00) 

(Froc.)     | 

Random  and  true. 


(20.00) 
1       80 

(Frac.)              (20.00) 
3                          2 

(2O.  OO) 
\ 

r  " 

4                          5 

6 


1      80 

(20.00) 

r        -     "     ^p^Ss^^^^^ 

'  1 

_||         Show/7  as 
'  ~|           regular. 

'   1 

(Frac.)       ^ 

South  boundary  of  section  out  of  limits  in  measurement;  southeast  quarter  protracted 
as  surveyed;  and  section  to  be  completed. 


194 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


Fig.  58. 

Ron dom  ond  true. 


(20.00) 

(Frac.)   \       i 

\ 

3         » 

2 

\ 

» 

| 

,     \ 

^1 

§       80 

»  

ll 

\ 

1 

•^1 

4          1 

5  i 

e     J1 

\ 

\ 

\ 

i 

1 

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i      1 

|      80 

1 

H'i 

'  i 

Shown  as 
regular. 

Mid-point                 j§ 

Random  and  true. 


(20.00) 

(free.) 

i               f 

3 

2          |           •       .. 

SI 

g 

^       80 

_ 

"  "  I    i 

4 

5          (          6 

1 

1 

I 

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^^^^^^^w^w^w^v???! 

I 

j 

7   i 

| 

^ 

Shown  as 

^       80 

""  | 

regular. 

8 

1 

1 

Mid-i 

ix 

Jl 

East  boundary  of  section  out  of  limits  in  alinement;  southeast  quarter  protracted 
as  surveyed;  and  section  to  be  completed. 


SYSTEM   OF  RECTANGULAR   SURVEYS.  195 

old  lines.  It  must  be  granted  that  a  skillful  exercise  of  judg- 
ment by  the  surveyor  based  upon  his  knowledge  of  the  facts  is 
far  more  desirable  than  to  restrict  him  to  the  application  of 
empirical  rules  ^devised  to  cover  possible,  but  innumerable 
combinations  of  irregularity. 

9th.  The  completion  of  the  survey  of  the  partially  surveyed 
sections  will  be  made  as  nearly  as  possible  in  accordance  with 
the  regular  rules  for  subdividing  when  the  original  lines  are 
found  to  be  within  limits,  otherwise,  such  sections  will  be 
completed  by  surveying  all  lines  in  such  a  manner  that  each 
and  every  section  (excepting  in  cases  of  unavoidable  hiatus  or 
overlap)  shall  have  four  regular  boundaries  without  offsets, 
with  four  governing  section  corners  and  four  controlling  quarter- 
section  corners  in  such  positions  as  to  maintain  the  integrity  of 
the  fractional  areas  already  shown  upon  the  original  plat.  The 
subdivision  thereof  may  then  be  made  by  connecting  the  oppo- 
site quarter-section  corners  in  the  regular  manner  with  resulting 
locations  agreeable  to  the  legal  subdivisions  shown  upon  the 
original  plat.  If  an  hiatus  or  overlap  is  unavoidable,  the  position 
of  the  new  quarter-section  corner  or  corners  will  be  carefully 
determined  for  latitude  on  a  meridional  line  or  for  departure 
on  a  latitudinal  line  on  the  same  plan  as  would  have  resulted 
in  the  regular  survey  of  a  new  boundary  extending  in  full  from 
the  one  or  two  directions  which  control  the  position  of  the  new 
quarter-section  corner  or  corners. 

10th.  Adjoining  sections  must  be  considered  separately 
when  placing  the  new  quarter-section  corners,  and  the  new 
corner  need  not  be  common  to  the  four  quarters  of  the  two 
adjoining  sections  unless  the  theoretical  position  for  each  section 
falls  within  25  links  of  a  common  point  in  which  case  the  differ- 
ence may  be  adjusted  in  such  a  manner  as  to  secure  maximum 
regularity. 

217.  Let  it  be  assumed  that  adjacent  to  two  established  section 
lines,  the  meridional  line  of  which  is  out  of  limits  in  measurement, 
an  outlying  regular  quarter  section  has  been  protracted  as  surveyed; 
then  to  complete  the  section  the  new  section  lines  will  be  extended 
from  the  previously  established  section  corners,  parallel  to  the 
opposite  established  boundaries,  or  mean  course  thereof,  to  a  mutual 
intersection.  The  quarter-section  corner  on  the  new  latitudinal 
section  line  would  be  established  regularly  at  the  mean  point,  and 
would  ordinarily  be  marked  to  control  the  subdivision  of  two  sections. 
On  the  new  meridional  boundary  one  or  two  quarter-section  corners 
may  be  required;  one  marked  to  control  the  subdivision  of  the  section 
under  consideration  will  be  established  at  40  chains  from  the  original 
section  corner;  the  same  quarter-section  corner  would  be  marked  to 
control  the  subdivision  of  the  adjoining  section  if  the  fractional 


196  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

Fig.  59. 

*•*  Wf>*z  + 


Mid-point 


80 


80 


1 


jv  Shown  as 

|  regular. 

I 


West 


t 

§ 

80 

Mid-point 

80 

.c 
o 

\ 

\i 

Q; 

\ 

^ 

5 

I            \ 

2                         34 

^5: 

^ 

\ 

\ 
\  

m^xm^ 

;\\^ 

\ 

|§r^ 

1 

\ 
6           } 

\ 

;  1 

1 

\ 

—            -j- 

\ 

7           \ 

_^          Shown  OS 
regular. 

8     1 

§ 

\ 

^ 

Mid-point 

1  

South  boundary  of  section  out  of  limits  in  alinement;  southeast  quarter  protracted 
as  surveyed;  and  section  to  be  completed. 


SYSTEM   OF   RECTANGULAR   SURVEYS.  197 

measurement  is  to  be  thrown  in  the  same  direction  in  the  two  sec- 
tions, otherwise  an  additional  quarter-section  corner  marked  to 
control  the  subdivision  of  the  adjoining  section  would  ordinarily 
be  placed  at  40  chains  from  the  new  section  corner.  Again,  let  the 
same  condition  be  assumed  with  the  exception  that  the  latitudinal 
section  line  instead  of  the  meridional  line  is  found  to  be  defective  in 
measurement.  Then,  to  complete  the  section,  the  new  meridional 
line  would  be  surveyed  as  in  regular  subdivision,  parallel  to  the 
opposite  meridional  line,  or  mean  course  thereof,  ordinarily  with 
quarter-section  and  section  corners  of  maximum  control  at  40  and 
80  chains,  respectively.  The  new  latitudinal  section  line  would  then 
be  established  on  a  true  line  between  the  section  corners,  and  one  or 
two  quarter-section  corners  will  be  established  as  required;  one 
marked  to  control  the  subdivision  of  the  section  under  consideration 
will  be  established  at  40  chains  from  the  original  section  corner;  the 
same  quarter-section  corner  would  be  marked  to  control  the  sub- 
division of  the  adjoining  section  if  the  fractional  measurement  is 
to  be  thrown  in  the  same  direction  in  both  sections,  otherwise  an 
additional  quarter-section  corner  marked  to  control  the  subdivision 
of  the  adjoining  section  would  ordinarily  be  placed  at  40  chains  from 
the  new  section  corner. 

218.  Let  another  assumption  be  made  that  adjacent  to  two  estab- 
lished section  lines,  the  meridional  line  of  which  is  out  of  limits  in 
alinement,  an  outlying  regular  quarter  section  has  been  protracted 
as  surveyed;  then  to  complete  the  section,  the  new  meridional  line 
will  be  projected  as  a  sectional  guide  meridian,  in  accordance  with 
the  usual  rules,  ordinarily  with  quarter-section  and  section  corners 
of  maximum  control  at  40  and  80  chains,  respectively.  The  new 

latitudinal  section  line  would  then  be  established  on  a  true  line 

• 

between  the  section  corners,  with  one  or  two  quarter-section  corners 
as  required;  one  marked  to  control  the  subdivision  of  the  section 
under  consideration  will  be  required  at  40  chains  from  the  original 
section  corner;  the  same  quarter-section  corner  would  be  marked 
to  control  the  subdivision  of  the  adjoining  section  if  the  fractional 
measurement  is  to  be  thrown  in  the  same  direction  in  both  sections; 
otherwise  an  additional  quarter-section  corner  marked  to  control 
the  subdivision  of  the  adjoining  section  will  ordinarily  be  established 
at  40  chains  from  the  new  section  corner.  On  the  other  hand,  if 
the  same  conditions  be  assumed  with  the  exception  that  the  original 
latitudinal  section  line  instead  of  the  meridional  line  is  found  to  be 


198 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


Fig.  60. 

Poratlel'to  South  bdy 

| 

f20.00J    '    (Frac.) 
40                     3 

\      f  2O.OO  t     \      (  2O.OO  j 
*                          \                     S 

1       2      1      '     1 

»                         1 

*•* 

| 
| 

4                     5 



9                     8 

10                    11 

Mid-point 

"t                      ~~1 

'           "o 

1            617? 
'                      ',                  * 

1 
^           Shown  as 

^            regular 

\ 

Parallel  to  South  bdy. 


(20.00) 
\      40 

Vj 

(Frac)      i     (2000) 

3             i           2 
I 

(2O.OO) 
1         S 

§ 

[_ 

-                 H 

1 

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1      4 

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7      c 

. 

i 



t      9 

8 

.  _|         Shown 

^5- 
7/7 

Mid-i 

reguk 

" 

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East  boundary  of  section  out  of  limits  in  alinement  and  measurement; 
quarter  protracted  as  surveyed;  and  section  to  be  completed. 


SYSTEM  OF  RECTANGULAR  SURVEYS. 
Fiq.61. 


199 


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South  boundary  of  section  out  of  limits  in  alinement  and  measurement;  southeast 
quarter  protracted  as  surveyed;  and  section  to  be  completed. 


200  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

defective  in  alinement,  then  the  new  latitudinal  section  line  will 
have  to  be  established  as  a  sectional  correction  line,  exactly  in 
accordance  with  the  rules  already  given  for  running  such  lines, 
ordinarily  with  section  corner  of  maximum  control  at  its  inter- 
section with  the  new  meridional  section  line,  and  quarter-section 
corner  of  maximum  control  at  mid-point.  On  the  new  meridional 
section  line  one  or  two  quarter-section  corners  may  be  required; 
one  marked. to  control  the  subdivision  of  the  section  under  consid- 
eration will  be  established  at  40  chains  from  the  original  section 
corner;  the  same  quarter-section  corner  may  be  marked  to  control 
the  subdivision  of  the  adjoining  section  if  the  fractional  measure- 
ment is  to  be  placed  in  the  same  direction  in  the  two  sections,  but 
if  the  fractional  measurement  is  to  be  thrown  in  the  opposite  direction 
in  the  adjoining  section  an  additional  quarter-section  corner  marked 
to  control  the  subdivision  of  that  section  would  ordinarily  be  re- 
quired at  40  chains  from  the  new  section  corner. 

219.  Many  cases  will  arise  in  the  field  involving  combinations 
of  two  or  more  of  the  above  simple  examples,  in  which  instance 
the  surveyor  is  advised  to  prepare  a  diagram  illustrating  the  con- 
ditions found  in  the  original  survey,  whereupon  the  new  section 
lines  may  be  shown  with  alinement  in  accordance  with  the  usual 
rules  for  subdividing  townships,  noting  that  the  new  section  lines 
are  to  be  initiated  at  the  previously  established  original  section 
corners,  and  that  the  length  of  the  meridional  boundary  will  depend 
both  upon  the  regularity  of  the  length  of  the  opposite  original  merid- 
ional section  line  and  upon  the  alinement  of  the  previously  estab- 
lished latitudinal  section  line;  thereupon  the  surveyor  may  at  once 
show  upon  his  diagram  the  position  of  the  necessary  quarter-section 
corners  on  the  new  section  lines,  all  in  conformity  with  the  simple 
rules  already  stated. 

220.  Other  instances  will  be  found  where  half  sections  are  shown 
upon  the  original  approved  plat  protracted  as  surveyed,  in  some 
cases  where  only  the  opposite  section  line  has  not  been  established 
and  in  other  cases  where  parts  of  the  adjacent  as  well  as  the  opposite 
section  lines  have  not  been  established.    In  case  only  one  section 
line  remains  to  be  established,  it  will  be  located  upon  the  true  line 
connecting  the  original  section  corners,  regardless  of  bearing;  the 
new  opposite  quarter-section  corner  marked  to  control  the  subdi- 
vision of  the  stated  section  will  be  placed  at  mid-point,  regardless 
of  the  length  of  the  new  section  line;  the  position  of  the  quarter- 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


201 


New 


Fig.62. 

Para//e/  to  5.  bdy. 


0/d 


M/d-point        Mid-point        Mid-point 


Shown  as  regular. 


Shown  as  regular. 


Old  bdrs. defective  in  measurement. 

flew  West 0/d 


Mid-point        Mid-point        Mid-point 


Shown  as regulqr.    •  Shown  as  regular. 


Old  bdrs.  defective  in  alinement 

South  half  protracted  as  surveyed,  and  section  to  be  completed. 
55465°— 19 14 


202  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

C/Q- 


Old  bdrs. defective  in  measurement. 
Random  and  true.      . 


Olcf 


Mid-point       Mid-point        Mid-point 


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Shown  as  reg> 


ulaf. 


Old  bdrs. defective  in  afinement. 
South  half  protracted  as  surveyed,  and  section  to  be  completed* 


SYSTEM  OF  RECTANGULAR  SURVEYS. 


203 


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Regular 

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Old  surveys  irregular;  protracted  areas  shown  as  fractional;  and  section  to  be 
completed. 


204  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

section  corner  marked  to  control  the  subdivision  of  the  adjoining 
section  will  depend  upon  the  plan  of  subdividing  the  remaining 
public  land.  Partially  surveyed  section  lines  will  be  completed 
by  extension,  the  alinement  of  the  same  being  governed  by  the 
usual  rules  for  regular  subdivision;  the  latitudinal  or  meridional 
position  of  the  remaining  section  line  (opposite  to  the  half  section 
protracted  as  surveyed)  will  usually  be  controlled  by  the  position 
of  the  nearest  original  section  corner,  and  the  alinement  of  the  same 
will  depend  upon  the  usual  rules  for  regular  subdivision;  the  new 
opposite  quarter-section  corner  marked  to  control  the  subdivision 
of  the  section  containing  such  half  section  protracted  as  surveyed 
will  be  placed  at  mid-point  in  every  case ;  the  position  of  the  quarter- 
section  corner  marked  to  control  the  subdivision  of  the  adjoining 
section  will  depend  upon  the  manner  of  subdividing  the  remaining 
public  land. 

221.  Various  other  examples  will  be  found  where  fractional  areas, 
as  along  the  north  or  west  boundary  of  a  township,  are  shown  upon 
the  original  approved  plat  protracted  as  surveyed.     In  all  such 
instances  the  same  rules,  heretofore  stated,  may  be  applied,  with  the 
single  exception  that  a  calculation  must  be  made,  based  upon  the 
areas  shown  upon  the  original  plat,  of  the  theoretical  lengths  of  all 
lines  not  established  in  the  original  survey.    Such  calculated  distances 
will  then  control  instead  of  the  usual  regular  lengths  of  section  lines 
as  heretofore  assumed;  also,  if  such  calculated  distances  count  from 
two  directions,  and  irregularities  are  developed,  the  calculations 
must  again  be  resolved  into  proportional  distances  to  agree  with 
actual  measurements  between  the  controlling  points. 

222.  On  the  accompanying  diagrams  are  shown  various  exagger- 
ated examples  of  the  manner  of  completing  the  survey  of  irregular 
sections  containing  outlying  areas  protracted  as  surveyed,  showing 
the  application  of  the  means  necessary  for  the  protection  of  the 
integrity  of  such  areas.     It  is  recognized  that  the  general  principles 
above  set  forth  will  not  always  permit  the  complete  establishment 
and  appropriate  marking  of  all  corners  at  the  first  determination  of 
their  locations,  by  reason  of  the  fact  that  only  the  bringing  up  of  the 
new  surveys  to  be  closed  upon  the  completed  units  will  develop 
the  appropriate  markings  of  the  finished  corner,  but  this  need  not 
impair  the  surveyor's  confidence  in  his  knowledge  of  necessary  pro- 
cedure in  the  initiatory  work,  to  be  recognized  and  applied  appro- 
priately when  the  new  surveys  are  brought  up  to  their  closings. 


SYSTEM  OF  RECTANGULAR  SURVEYS.  205 

223.  A  distinctly  different  class  of  partially  surveyed  sections  is 
found  along  erroneous  meander  lines  shown  upon  approved  plats  of 
fractional  townships.    Such  sections  are  never  subject  to  completion 
except  as  definitely  authorized  in  the  written  special  instructions 
furnished  to  the  surveyor,  as  the  approved  plat  must  be  held  to 
represent  correctly  a  true  meanderable  body  of  water  until  proven 
otherwise  to  the  satisfaction  of  the  Department  of  the  Interior,  as 
intimated  in  Chapter  I.    Numerous  instances  are  on  record,  how- 
ever, where  the  evidence  submitted  to  the  Department  is  con- 
clusive that  surveyors  have  erroneously  classified  overflowed  lands 
as  meanderable,  or  where  the  recorded  meander  line  does  not  and 
never  did  conform  to  the  mean  high-water  elevation  of  an  actual 
meanderable  body  of  water,  thus  erroneously  omitting  considerable 
areas  of  land.    The  questions  of  title  to  such  areas  are  extremely 
intricate,  and  it  is  the  practice  of  the  General  Land  Office  not  to 
allow  any  extension  of  such  original  surveys  until  the  procedure  has 
been  definitely  authorized  by  the  Secretary  of  the  Interior.    The 
surveying  problems  arise  only  when  the  extension  of  the  original 
survey  beyond  the  meander  line  shown  upon  the  approved  plat  has 
been  duly  authorized. 

The  reestablishment  of  the  original  meander  line  with  a  suitable 
monument  at  each  angle  point  is  a  usual  accompaniment  of  the 
above  class  of  surveys,  the  purpose  being  to  segregate  definitely  the 
previously  surveyed  areas  from  the  unsurveyed  public  lands;  it  is 
more  appropriate  to  consider  the  surveying  questions  thus  involved 
along  with  other  problems  relating  to  the  reestablishment  of  broken 
boundaries,where  the  subject  will  be  found  in  sec.  380,Chapter  V.  The 
next  step  in  the  field  is  to  complete  the  partially  surveyed  sections 
and  the  procedure  in  practically  every  instance  will  be  controlled 
by  the  rules  already  outlined  in  respect  to  the  completion  of  the 
survey  of  sections  containing  outlying  areas  protracted  as  surveyed; 
it  seems  unnecessary  to  repeat  the  governing  principles  in  such 
closely  related  cases. 

SUBDIVISION    OP   FRACTIONAL    SECTIONS    RESULTING   FROM 
FRAGMENTARY    SURVEYS. 

224.  The  one  best  test  of  the  fitness  of  a  proposed  method  incident 
to  the  completion  of  partially  surveyed  sections  will  be  found  in 
platting  the  section  for  subdivision  by  protraction;  thereupon  the 
regular  rules  for  subdivision  of  sections  should  be  applicable.     Thus 


206  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

Fig.  65    (West half) 


Example  showing  the  completion  of  partially  surveyed  sections,  the  subdivision  of 

resulting  from 


SYSTEM  OF  RECTANGULAR  SURVEYS. 

Fig.  65    (East  half) 


207 


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fractional  sections,  and  the  completion  of  the  subdivisional  lines  of  a  partial  township 
fragmentary  surveys. 


208  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

the  position  of  the  new  quarter-section  corners,  established  to  con- 
trol the  subdivision  of  a  particular  section  in  question,  must  be  such 
as  to  permit  the  center  lines  from  said  points  to  the  opposite  original 
quarter-section  corners  to  be  connected  in  strict  harmony  with  the 
conditions  represented  upon  the  original  approved  plat,  disregard- 
ing the  effect  upon  the  subdivision  of  the  newly  surveyed  public 
land.  Likewise  the  lines  connecting  the  sixteenth-section  corners 
on  the  opposite  boundaries  of  a  quarter  section  must  conform  to  the 
conditions  represented  upon  the  original  plat.  When  the  subdi- 
vision-of-section  lines  are  thus  platted  the  section  may  be  considered 
satisfactory  if  the  integrity  of  the  original  areas  is  in  no  way  violated. 
When  the  subdivision-of-section  lines  are  platted  as  suggested,  the 
permanent  conditions  affecting  the  new  areas  may  be  considered,  and 
should  be  harmonized  with  the  following  additional  rules: 

1st.  The  new  areas  should  be  complementary  to  the  original  areas 
by  the  extension  of  the  subdivision-of-section  lines  as  already  pro- 
tracted upon  the  original  plat,  except  as  poorly  shaped  lots,  or  lots 
of  too  great  or  too  little  area,  would  result  in  violation  of  the  regular 
rules  for  subdivision  of  sections. 

2d.  The  same  meridional  limit  may  be  permitted,  in  the  interest 
of  regularity  and  simplicity  of  platting,  as  is  ordinarily  allowed  in 
latitudinal  section  lines;  i.  e.,  a  section  may  be  considered  regular 
whose  boundary  lines  are  all  for  alinement  when  not  to  exceed  21/ 
from  a  cardinal  course,  and  for  measurement  when  not  to  exceed  25 
links  from  40  chains  between  the  section  and  quarter-section  corners. 
Such  regular  sections  may  be  subdivided  into  regular  quarter  sec- 
tions and  quarter-quarter  sections  as  far  as  possible.  A  section 
having  three  regular  boundary  lines  may  be  subdivided  in  accord- 
ance with  the  usual  rules  for  subdividing  sections  along  the  north 
and  west  boundaries  of  a  normal  township.  A  section  having  two 
adjacent  regular  boundary  lines  may  be  subdivided  similarly  to  the 
manner  in  which  section  6  of  a  normal  township  is  "treated.  All 
other  sections  should  be  treated  as  irregular,  with  subdivision-of- 
section  lines  protracted  to  mid-points  on  the  boundaries  of  the 
quarter  sections,  except  as  a  calculated  proportional  position  for 
a  sixteenth-section  corner  is  made  necessary  by  reason  of  conditions 
relating  to  the  complementary  area  shown  upon  the  original  plat. 

3d.  All  new  fractional  lots  will  be  numbered  beginning  with  the 
next  higher  number  in  the  series  of  the  same  section  already  begun 
upon  the  previously  approved  plat,  and  proceeding  in  the  usual 


SYSTEM  OF  RECTANGULAR  SURVEYS.  209 

order  in  which  fractional  lots  are  normally  numbered.  The  new 
series  may  begin  with  No.  1  in  case  the  fractional  parts  of  the  original 
area  are  not  designated  by  lot  number. 

COMPLETING   THE    SUBDIVISION    OF  A   PARTIAL  TOWNSHIP   RESULTING 
FROM   FRAGMENTARY   SURVEYS. 

225.  After  the  partially  surveyed  sections  have  been  fully 
completed  the  surveyor  may  proceed  with  the  subdivision  of  the 
remaining  portions  of  the  township.  Every  condition  represents 
a  separate  problem,  and  few  specific  rules  would  serve  any  purpose 
in  guiding  the  surveyor  to  a  definite  procedure.  If  no  irregularities 
are  to  be  found  in  the  previously  established  lines  the  new  survey 
may  proceed  normally,  but  if  defective  conditions  are  encountered 
the  irregularities  are  not  to  be  extended  into  unsurveyed  sections 
any  farther  than  necessary  to  incorporate  the  resulting  fractional 
measurements  into  suitable  fractional  lots  adjoining  the  former 
surveys.  Preference  should  be  given  to  extending  all  surveys  from 
south  to  north  and  from  east  to  west,  but  if  a  better  control  is 
available  by  reversing  the  procedure  in  one  or  both  directions, 
thus  resulting  in  a  simpler  and  better  survey  in  respect  to  mini- 
mizing the  number  of  extra  comers  as  well  as  fractional  lots,  such 
reversal  of  procedure  is  fully  warranted.  The  principle  relating  to 
controlling  coordinate  measurements  in  two  directions  at  right 
angles,  as  along  the  south  and  east  boundaries  of  a  township,  may 
be  applied  to  the  subdivisional  lines  best  suited  to  control  the  new 
surveys  to  be  executed;  and,  if  the  selected  bases  are  defective  in 
alinement,  in  whole  or  in  part,  the  new  section  lines  may  serve 
the  function  of  a  sectional  guide  meridian  or  a  sectional  correction 
line  as  required.  The  corners  from  which  the  new.  surveys  are  to 
be  initiated  and  controlled  in  latitude  and  departure  will  be  termed 
corners  of  four  sections,  or  of  two  sections  as  appropriate,  and  where 
the  terminal  lines  can  not  be  connected  regularly  with  the  pre- 
viously established  section  corners  by  random  and  true  line  not 
exceeding  2V  from  cardinal,  a  closing  section  corner  will  be 
established  in  full  accord  with  the  principle  relating  to  the  estab- 
lishment of  closing  section  corners  on  the  north  or  west  boundaries 
of  a  township  where  the  latter  lines  are  found  to  be  defective  in 
measurement.  The  fractional  measurements  of  the  closing  section 
lines  will  be  placed  adjacent  to  the  old  surveys,  and  the  distance 
from  the  closing  section  corner  to  the  nearest  original  corner  will 


210  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

Fig.  66   (West  half ) 


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Exairmlfi  sho-sriner  tha  nnrrmlp.tion  of  t.ho  snhdivisional 


SYSTEM  OF  RECTANGULAR  SURVEYS. 

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211 


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of  a  partial  township  resulting  from  fragmentary  surveys. 


212  MANUAL  OF  .SURVEYING  INSTRUCTIONS. 

be  measured;  the  original  lines  forming  the  boundary  of  the  lands 
to  be  surveyed  will  be  retraced,  as  already  provided,  and  the  marks 
upon  the  original  corners  will  be  appropriately  modified  as  neces- 
sary; new  quarter-section  corners  marked  to  control  the  subdivision 
of  the  new  sections  will  be  established  on  the  original  lines  at  mid- 
points between  the  closing  section  corners,  or  at  40  chains  from  one 
direction,  according  to  the  manner  in  which  a  new  section  is  to  be 
subdivided. 

There  are  generally  two  or  more  ways  in  which  a  fragmentary 
subdivision  may  be  executed,  but  a  careful  study  of  a  sketch  plat 
representing  existing  conditions  will  generally  reveal  the  superi- 
ority of  one  method  over  another,  and  objectionable  results  should 
be  avoided  as  far  as  existing  conditions  relating  to  the  original 
surveys  will  permit. 

MEANDERING. 

226.  All  navigable  bodies  of  water  and  other  important  rivers 
and  lakes  (as  hereinafter  described)  are  to  be  segregated  from  the 
public  lands  at  mean  high- water  elevation.  The  traverse  of  the 
margin  of  a  permanent  natural  body  of  water  is  termed  a  meander 
line. 

The  running  of  meander  lines  has  always  been  authorized  in  the 
survey  of  public  lands  fronting  on  large  streams  and  other  bodies  of 
water,  but  the  mere  fact  that  an  irregular  or  sinuous  line  must  be 
run,  as  in  case  of  a  reservation  boundary,  does  not  entitle  it  to  be 
called  a  meander  line  except  where  it  closely  follows  the  bank  of  a 
stream  or  lake.  The  legal  riparian  rights  connected  with  meander 
lines  do  not  apply  in  case  of  other  irregular  lines,  as  th*e  latter  are 
strict  boundaries. 

Mean  high-water  mark  has  been  defined  in  a  State  decision  (47 
Iowa,  370)  in  substance  as  follows:  High-water  mark  in  the  Missis- 
sippi River  is  to  be  determined  from  the  river  bed;  and  that  only 
is  river  bed  which  the  river  occupied  long  enough  to  wrest  it  from 
vegetation.  In  another  case  (14  Perm.  St.,  59)  a  bank  is  defined  as 
the  continuous  margin  where  vegetation  ceases,  and  the  shore  is  the 
sandy  space  between  it  and  low- water  mark. 

Numerous  decisions  in  the  United  States  Supreme  Court  and 
many  of  the  State  courts  assert  the  principle  that  meander  lines 
are  not  boundaries  defining  the  area  of  ownership  of  tracts  adjacent 
to  waters.  The  general  rule  is  well  set  forth  (10  Iowa,  549)  by 
saying  that  in  a  navigable  stream,  as  the  Des  Moines  River  in  Iowa, 


SYSTEM  OF  RECTANGULAR   SURVEYS.       t  213 

high- water  mark  is  the  boundary  line.  When  by  action  of  the 
water  the  river  bed  changes,  high-water  mark  changes  and  owner- 
ship of  adjoining  land  progresses  with  it. 

Meander  lines  will  not  be  established  at  the  segregation  line 
between  upland  and  swamp  or  overflowed  land,  but  at  the  ordinary 
high-water  mark  of  the  actual  margin  of  the  river  or  lake  on  which 
such  swamp  or  overflowed  lands  border. 

227.  Practically  all  inland  bodies  of  water  pass  through  an 
annual  cycle  of  changes  from  mean  low  water  to  flood  stages, 
between  the  extremes  of  which  will  be  found  mean  high  water. 
In  regions  of  broken  topography,  especially  where  bodies  of  water 
are  bounded  by  sharply  sloping  lands,  the  horizontal  distance 
between  the  margins  of  the  various  water  elevations  is  compara- 
tively slight,  and  the  surveyor  will  not  experience  much  difficulty 
in  determining  the  horizontal  position  of  mean  high-water  level 
with  approximate  accuracy;  but  in  level  regions,  or  in  any  locality 
where  the  meanderable  bodies  of  water  are  bordered  by  relatively 
flat  lands,  the  horizontal  distance  between  the  successive  levels  is 
relatively  great.  The  surveyor  will  find  the  most  reliable  indica- 
tion of  mean  high-water  elevation  in  the  evidence  made  by  the 
water's  action  at  its  various  stages,  which  will  generally  be  found 
well  marked  in  the  soil,  and  in  timbered  localities  a  very  certain 
indication  of  the  locus  of  the  various  important  water  levels  will  be 
found  in  the  belting  of  the  native  forest  species. 

Mean  high-water  elevation  will  be  found  at  the  margin  of  the 
area  occupied  by  the  water  for  the  greater  portion  of  each  average 
year;  at  this  level  a  definite  escarpment  in  the  soil  will  generally 
be  traceable,  at  the  top  of  which  is  the  true  position  for  the  surveyor 
to  run  the  meander  line.  A  pronounced  escarpment,  the  result  of 
the  action  of  storm  and  flood  waters,  will  often  be  found  above  the 
principal  water  level,  and  separated  from  the  latter  by  the  storm 
or  flood  beach ;  another  less  evident  escarpment  will  often  be  found 
at  the  average  low- water  level,  especially  of  lakes,  the  lower  escarp- 
ment being  separated  from  the  principal  escarpment  by  the  normal 
beach  or  shore.  While  these  questions  properly  belong  to  the  realm 
of  geology,  they  should  not  be  overlooked  in  the  survey  of  a  meander 
line. 

Where  native  forest  trees  are  found  in  abundance  bordering 
bodies  of  water,  those  trees  showing  evidence  of  having  grown  under 
favorable  site  conditions  will  be  found  accurately  belted  along 


214  ,    MANUAL  OF  SURVEYING  INSTRUCTIONS. 

contour  lines;  thus  a  certain  class  of  mixed  varieties  common  to  a 
particular  region  will  be  found  only  on  the  lands  seldom  if  ever 
overflowed;  another  group  of  forest  species  will  be  found  on  the 
lands  which  are  inundated  only  a  small  portion  of  the  growing  season 
each  year,  and  indicate  the  area  which  should  be  included  in  the 
classification  of  the  uplands;  other  varieties  of  native  forest  trees 
will  be  found  only  within  the  zone  of  swamp  and  overflowed  lands. 
All  timber  growth  normally  ceases  at  the  margin  of  permanent  water. 

228.  At  every  point  where  either  standard,  township  or  section 
lines  intersect  the  bank  of  a  navigable  stream,  or  any  meanderable 
body  of  water,  corners  at  such  intersections  will  be  established  at 
the  time  of  running  these  lines.    Such  monuments  are  called  mean- 
der corners.     In  the  survey  of  lands  bordering  on  tide  waters,  mean- 
der corners  may  be  temporarily  set  at  the  intersection  of  the  sur- 
veyed lines  with  the  margin  of  mean  high  tide,  but  no  monument 
should  be  placed  in  a  position  exposed  to  the  beating  of  waves  and 
the  action  of  ice  in  severe  weather.    In  all  such  cases  a  witness 
corner  on  the  line  surveyed,  at  a  secure  point  near  the  true  point 
for  the  meander  corner,  will  be  established.    The  crossing  distance 
between  meander  corners  on  the  same  line  will  be  ascertained  by 
triangulation  or  direct  measurement,  and  the  full  particulars  will  be 
given  in  the  field  notes. 

229.  Inasmuch  as  it  is  not  practicable  in  public-land  surveys  to 
meander  in  such  a  way  as  to  follow  and  reproduce  all  the  minute 
windings  of  the  high-water  line,  the  United  States  Supreme  Court 
has  given  the  principles  governing  the  use  and  purpose  of  meandering 
shores  in  its  decision  in  a  noted  case  (R.  B.  Co.  v.  Schurmeir,  7 
Wallace,  286-287)  as  follows: 

"  Meander  lines  are  run  in  surveying  fractional  portions  of  the 
public  lands  bordering  on  navigable  rivers,  not  as  boundaries  of 
the  tract,  but  for  the  purpose  of  defining  the  sinuosities  of  the  .banks 
of  the  stream,  and  as  the  means  of  ascertaining  the  quantity  of  land 
in  the  fraction  subject  to  sale,  which  is  to  be  paid  for  by  the  pur- 
chaser. In  preparing  the  official  plat  from  the  field  notes,  the  mean- 
der line  is  represented  as  the  border  line  of  the  stream,  and  shows  to 
a  demonstration  that  the  water-course,  and  not  the  meander  line  as 
actually  run  on  the  land,  is  the  boundary." 

230.  The  surveyor  will  commence  the  meander  line  at  one  of 
the  meander  corners,  follow  the  bank  or  shore  line,  and  determine 
the  true  bearing  and  measure  the  exact  length  of  each  course,  from 


SYSTEM  OF  RECTANGULAR  SURVEYS.  215 

the  beginning  to  the  next  meander  corner.  All  meander  courses 
are  to  be  taken  or  counted  from  the  true  meridian  and  will  be  de- 
termined with  precision;  "transit  angles"  showing  only  the  amount 
of  the  deviation  from  the  preceding  course  are  not  acceptable  in 
field  notes  of  meanders.  For  convenience  the  courses  of  meander 
lines  should  be  adjusted  to  the  exact  quarter  degree;  meander 
lines  are  not  strict  boundaries  and  this  method  will  give  approxi- 
mate agreement  with  the  minute  sinuosities  of  mean  high-water 
elevation.  Again,  for  convenience  of  platting  and  computation, 
the  surveyor  is  required  to  adopt  turning  points  at  distances  of  whole 
chains,  or  multiples  of  ten  links,  with  odd  links  only  in  the  final 
course. 

In  cases  where  the  surveyor  finds  it  impossible  to  carry  his  meander 
line  along  mean  high-water  mark,  his  notes  should  state  the  distance 
therefrom  and  the  obstacles  which  justify  the  deviation.  A  table 
of  latitudes  and  departures  of  the  meander  courses  should  be  com- 
puted before  leaving  the  vicinity,  and  if  misclosure  is  found,  indi- 
cating error  in  measurement  or  in  reading  courses,  the  lines  should 
be  rerun. 

All  streams  flowing  into  a  river,  lake  or  meanderable  bayou 
will  be  noted,  and  the  width  at  their  mouths  stated;  also,  the  posi- 
tion, size  and  depth  of  springs,  whether  the  water  be  pure  or  min- 
eral; also,  the  heads  and  mouths  of  all  bayous,  all  rapids  and  bars, 
will  be  noted,  with  intersections  to  the  upper  and  lower  ends  of  the 
latter,  to  establish  their  exact  situation.  The  elevation  of  the 
banks  of  lakes  and  streams,  the  height  of  falls  and  cascades,  and 
the  length  and  fall  of  rapids,  will  be  recorded  in  the  field  notes. 

The  field  notes  of  meanders  will  show  the  corners  from  which  the 
meanders  commenced  and  upon  which  they  closed,  and  will 
exhibit  the  meanders  of  each  fractional  section  separately ;  following, 
and  composing  a  part  of  such  notes,  will  be  given  a  description  of  the 
adjoining  land,  soil  and  timber,  and  the  depth  of  inundation  to 
which  the  bottom  land  is  subject.  The  utmost  care  will  be  taken 
to  pass  no  object  of  topography,  or  change  therein,  without  giving  a 
particular  description  thereof  in  its  proper  place  in  the  notes  of  the 

meanders. 

RIVERS. 

231.  Proceeding  downstream,  the  bank  on  the  left  hand  is  termed 
the  left  bank  and  that  on  the  right  hand  the  right  bank.  These 
terms  will  be  universally  used  to  distinguish  the  two  banks  of  a 


216  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

river  or  stream.  Navigable  rivers  and  bayous,  as  well  as  all  rivers 
not  embraced  in  the  class  denominated  " navigable,"  the  right- 
angle  width  of  which  is  3  chains  and  upwards,  will  be  mean- 
dered on  both  banks,  at  the  ordinary  mean  high-water  mark,  by 
taking  the  general  courses  and  distances  of  their  sinuosities.  Rivers 
not  classed  as  navigable  will  not  be  meandered  above  the  point 
where  the  average  right-angle  width  is  less  than  3  chains,  except 
that  streams  which  are  less  than  3  chains  wide  and  which  are  so 
deep,  swift  and  dangerous  as  to  be  impassable  may  be  meandered, 
where  good  agricultural  lands  along  the  banks  require  their  separa- 
tion into  fractional  lots  for  the  benefit  of  settlers. 

Shallow  fresh- water  streams,  without  any  well-defined  channel  or 
permanent  banks,  will  not  be  meandered.  Tidewater  streams, 
whether  more  or  less  than  3  chains  wide,  should  be  meandered  at 
ordinary  high-water  mark,  as  far  as  tidewater  extends. 

LAKES. 

232.  The  meanders  of  all  lakes  of  the  area  of  25  acres  and  up- 
wards, will  be  commenced  at  a  meander  corner  and  continued,  as 
above  directed  for  navigable  streams;  from  said  corner,  the  courses 
and  distances  of  the  entire  margin  of  the  same,  and  the  intersections 
witn  all  meander  corners  established  thereon,  will  be  noted. 

In  the  case  of  lakes  which  are  found  to  be  located  entirely  within 
the  boundaries  of  a  section,  a  quarter-section  line,  if  one  crosses 
the  lake,  will  be  run  from  one  of  the  quarter-section  corners,  on  a 
theoretical  course  to  connect  with  the  opposite  quarter-section 
corner,  to  the  margin  of  the  lake,  and  the  distance  will  be  measured ; 
then  at  the  point  thus  determined  a  "special  meander  corner"  will 
be  established.  If  a  meanderable  lake  is  found  to  be  located  en- 
tirely within  a  quarter  section,  an  "auxiliary  meander  corner"  will 
be  established  at  some  suitable  point  on  its  margin,  and  a  connect- 
ing line  will  be  run  from  said  monument  to  a  regular  corner  on  the 
section  boundary.  A  connecting  traverse  line  will  be  recorded,  if 
one  is  run,  but  it  will  also  be  reduced  to  the  equivalent  direct  con- 
necting course  and  distance,  all  of  which  will  be  stated  in  the  field 
notes,  and  the  course  and  length  of  the  direct  connecting  line  will  be 
be  shown  on  the  plat  of  the  survey. 

The  meander  line  of  a  lake  lying  within  the  interior  of  a  section 
will  be  initiated  at  the  established  special  or  auxiliary  meander 
corner,  as  the  case  may  be,  and  continued  around  the  margin  of  the 


SYSTEM  OF  RECTANGULAR  SURVEYS.  217 

normal  lake  at  its  mean  high- water  level,  to  a  closing  at  the  point 
of  beginning.  All  proceedings  are  to  be  fully  entered  in  the  field 
notes. 

Artificial  lakes  and  reservoirs  are  not  to  be  segregated  from  the 
public  lands,  unless  specially  provided  in  the  instructions,  but  the 
true  position  and  extent  of  such  bodies  of  water  will  be  determined 
in  the  field  and  shown  on  the  plat. 

ISLANDS. 

233.  In  the  progress  of  the  regular  surveys  every  island  above  the 
mean  high-water  elevation  of  any  meanderable  body  of  water,  ex- 
cepting only  those  islands  which  may  have  formed  in  navigable  bodies 
of  water  after  the  date  of  the  admission  of  a  State  into  the  Union,  will 
be  definitely  located  by  triangulation  or  direct  measurement  or 
other  suitable  process,  and  will  be  meandered  and  shown  upon  the 
official  plat. 

In  the  survey  of  th£  mainland  fronting  on  any  non-navigable 
body  of  water,  any  island  opposite  thereto,  above  mean  high- water 
elevation,  is  subject  to  survey.  Also,  even  though  the  United 
States  may  have  parted  with  its  title  to  the  adjoining  mainland,  an 
island  in  any  meandered  body  of  water,  navigable  or  non-navigable, 
known  or  proven  to  have  been  in  existence  at  the  date  of  the  admis- 
sion of  a  State  into  the  Union,  and  at  the  date  of  the  survey  of  the 
mainland,  if  omitted  from  said  original  survey,  remains  public  land 
of  the  United  States,  and  as  such  the  island  is  subject  to  survey. 

The  survey  of  islands  not  shown  upon  the  original  approved  plats 
of  subdivided  townships  is  authorized  by  the  Department  only  upon 
the  receipt  of  formal  application,  and  subject  to  the  approval  thereof. 
The  proof  of  the  time  of  the  formation  of  such  islands  is  often  more  or 
less  difficult,  and  it  is  the  practice  of  the  Department  to  make  a 
careful  examination  of  the  history  of  an  island  in  relation  to  the 
question  of  its  legal  ownership  before  approving  the  application  for 
its  survey. 

Any  township  boundary  or  section  line  which  will  intersect  an 
island  will  be  extended  as  nearly  in  accordance  with  the  plan  of 
regular  surveys  as  conditions  will  permit,  and  the  usual  township, 
section,  quarter-section  and  meander  corners  will  be  established 
on  the  island.  If  an  island  falls  in  two  sections  only,  the  line  be- 
tween those  particular  sections  should  be  established  in  its  proper 
theoretical  position  based  upon  suitable  sights  and  calculations. 
55465 Q— 19 15 


218  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

If  an  island  falls  entirely  in  one  section,  and  is  large  enough  to  be 
subdivided  (over  50  acres  in  area),  a  suitable  sight  or  calculation 
will  be  made  to  locate  on  the  margin  of  the  island  an  intersection 
with  the  theoretical  position  of  any  suitable  subdivision-of-section 
line,  and  at  the  point  thus  determined  a  "special  meander  corner'* 
will  be  established.  In  the  case  of  an  island  falling  entirely  in  one 
section  and  found  to  be  too  small  to  be  subdivided,  an  ''auxiliary 
meander  corner"  will  be  established  at  any  suitable  point  on  its 
margin,  which  will  be  accurately  connected  with  any  regular  cor- 
ner  on  the  mainland.  The  direct  course  and  length  of  the  connect- 
ing line  will  be  given  in  the  field  notes,  together  with  all  sights, 
measurements,  triangulations  and  traverse  lines  upon  which  the 
calculation  may  be  based.  The  course  and  length  of  the  direct  con- 
necting line  will  be  shown  on  the  plat. 

The  meander  line  of  an  island  will  be  surveyed  in  harmony  with 
principles  and  rules  heretofore  stated ;  all  township  and  section  lines 
crossing  the  island  will  be  shown  on  the  plat;  and,  if  the  island  is 
large  enough  to  be  subdivided,  the  subdivision  will  be  accomplished 
by  the  protraction  of  suitable  subdivision-of-section  lines  in  their 
correct  theoretical  position. 

Agricultural  upland  within  the  limits  of  swamp  and  overflowed 
lands  should  be  so  classified  and  shown  upon  the  plat  accordingly, 
but  such  land  will  not  be  meandered  as  an  island. 

LIMITS   OF   CLOSURE. 

234:.  Under  the  general  subjects  of  "township  exteriors"  and 
''subdivision  of  townships"  certain  definite  limits  were  prescribed 
beyond  which  previously  established  surveys  are  classed  as  "de- 
fective," or  in  the  case  of  new  surveys  corrective  steps  are  required. 
Such  limits  constitute  the  standard  of  accuracy  of  the  United  States 
rectangular  surveys,  and,  for  convenience,  have  been  variously  re- 
ferred to  as  the  "rectangular  limit,"  "limit  for  the  control  of  new 
surveys,"  "limit  relating  to  defective  exteriors  and  section  lines," 
"limits  for  subdivision,"  etc.,  each  expression  having  been  formed 
to  suit  the  descriptive  exigency  of  the  text.  A  more  general  re- 
quirement known  as  the  "limit  of  closure"  will  be  applied  as  a  test 
of  the  accuracy  of  the  alinement  and  measurement  of  all  classes  of 
lines  embraced  in  any  closed  figure  incident  to  the  public-land  sur- 
veys, and  corrective  steps  will  be  required  wherever  this  test  dis- 
closes an  error  beyond  the  allowable  limit. 


SYSTEM  OF  RECTANGULAR  SURVEYS.  219 

The  " error  of  closure"  of  a  survey  may  be  defined,  in  general 
terms,  as  the  ratio  of  the  length  of  the  line  representing  the  equiva- 
lent of  the  errors  in  latitude  and  departure  (as  found  by  a  table  of 
latitudes  and  departures)  to  the  length  of  the  perimeter  of  the  figure 
constituting  the  survey;  but,  with  due  regard  for  the  controlling 
coordinate  governing  lines  of  a  rectangular  survey,  pronounced 
accuracy  in  latitude  will  not  be  permitted  to  offset  gross  error  in 
departure,  or  vice  versa,  and,  in  order  to  be  consistent  with  this 
fundamental  theory,  a  double  test  must  be  applied  in  place  of  the 
one  expressed  in  general  terms.  The  " limit  of  closure"  fixed  for 
the  United  States  rectangular  surveys  may  be  expressed  by  the 
fraction  T£T  provided  that  the  limit  of  closure  in  neither  latitude 
nor  departure  exceeds  -g-^,  and  where  a  survey  qualifies  under  the 
latter  limit  the  former  is  bound  to  be  satisfied;  thus  an  accumulative 
error  of  12J  links  per  mile  of  perimeter,  in  either  latitude  or  departure, 
will  not  be  exceeded  in  an  acceptable  survey.  The  limit  of  closure 
as  thus  expressed  may  be  applied  to  various  specific  conditions  as 
heretofore  stated. 

The  latitudes  and  departures  of  a  normal  section  shall  each  close 
within  50  links;  of  a  normal  range  or  tier  of  sections,  within  175 
links;  and  of  a  normal  township,  within  300  links.  The  boundaries 
of  each  fractional  section  including  irregular  claim  lines  or  meanders, 
or  the  meanders  of  an  island  or  lake  in  the  interior  of  a  section,  should 
close  within  a  limit  to  be  determined  by  the  fraction  -^y  when  the 
error  in  either  latitude  or  departure  is  considered  separately;  the 
same  rule  will  be  applied  to  all  broken  or  irregular  boundaries. 

Surveyors  are  required  to  compute  all  doubtful  closings  while  in 
the  field  in  the  immediate  vicinity  of  a  particular  line,  or  series  of 
lines,  in  question,  and  to  accomplish  all  necessary  corrective  work 

before  concluding  a  survey. 

i 

MARKING   LINES  BETWEEN   CORNERS. 

235.  The  marking  of  a  survey  upon  the  ground  in  such  a  manner 
as  to  fix  forever  the  position  of  the  legal  lines  in  relation  to  the 
earth's  surface  is  the  final  step  in  the  field  work,  and  is  accomplished 
in  three  ways,  which,  if  well  executed,  will  individually  or  collec- 
tively furnish  the  means  of  the  identification  of  the  survey  at  even 
remote  future  dates.  Careful  attention  to  these  details  is  one  of  the 
most  important  phases  of  the  surveyor's  field  work,  (a)  The  regular 
corners  of  the  public-land  surveys  are  marked  by  fixed  monuments 


220  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

of  specified  character  as  described  in  Chapter  IV;  (6)  the  relation  of 
the  officially  surveyed  lines  to  natural  topographical  features  is 
recorded  in  much  detail  as  hereinafter  outlined,  and  again  exem- 
plified in  the  specimen  field  notes;  and,  (c)  the  locus  of  the  legal 
lines,  wherever  living  timber  is  encountered,  is  plainly  marked 
upon  the  forest  trees,  which  is  accomplished  by  the  process  of 
"blazing"  and  by  "hack"  marks. 

A  "blaze  "  is  an  ax  mark  which  is  made  upon  a  tree  trunk  at  about 
breast  height,  in  which  a  flat  scar  is  left  upon  the  tree  surface.  The 
bark  and  a  very  small  amount  of  the  live  wood  tissue  are  removed, 
leaving  a  smooth  surface  which  forever  brands  the  tree.  The  size 
of  the  blaze  depends  somewhat  upon  the  size  of  the  tree,  but  is 
never  made  larger  than  the  surface  of  an  ax  blade;  a  blaze  5  or  6 
inches  in  height  and  from  2  to  4  inches  in  width  is  ample  to  mark 
any  tree. 

A  "hack"  is  also  an  ax  mark  which  is  made  upon  a  tree  trunk  at 
about  breast  height,  in  which  a  horizontal  notch  is  cut  into  the 
surface  of  the  tree.  The  notch  is  made  "V-shaped,"  and  is  cut 
through  the  bark  and  well  into  the  wood.  Two  hacks  are  cut  in 
order  to  distinguish  those  made  in  the  survey  from  accidental  marks 
resulting  from  other  causes;  a  vertical  section  of  the  completed 
official  hack  mark  resembles  a  "  double-  V  "  (<)  extending  across  a 
tree  from  2  to  6  inches  in  length,  depending  upon  the  diameter  of 
the  tree.  The  "hack"  and  "blaze"  marks  are  equally  permanent, 
but  so  different  in  character  that  one  mark  should  never  be  mistaken 
for  the  other. 

The  marking  of  trees  along  the  surveyed  lines  was  required  by 
law  as  positively  as  the  erection  of  monuments,  by  the  act  of  1796, 
which  is  still  in  force.  All  lines  on  which  are  to  be  established  the 
legal  corners  will  be  marked  after  this  method,  viz:  Those  trees 
which  may  be  intersected  by  the  line  will  have  two  hacks  or  notches 
cut  on  each  of  the  sides  facing  the  line,  without  any  other  marks 
whatever.  These  are  called  sight  trees  or  line  trees.  A  sufficient 
number  of  other  trees  standing  within  50  links  of  the  line,  on  either 
side  of  it,  will  be  blazed  on  two  sides  quartering  toward  the  line,  in 
order  to  render  the  line  conspicuous,  and  readily  to  be  traced  in 
either  direction,  the  blazes  to  be  opposite  each  other  coinciding 
in  direction  with  the  line  where  the  trees  stand  very  near  it,  and  to 
approach  nearer  each  other  toward  the  line  the  farther  the  line  passes 
from  the  blazed  trees. 


SYSTEM  OF  RECTANGULAR  SURVEYS.  221 

Due  care  will  ever  be  taken  to  have  the  lines  so  well  marked  as  to 
be  readily  followed,  and  to  cut  the  blazes  plainly  enough  to  leave; 
recognizable  scars  as  long  as  the  trees  stand.  This  can  be  accom- 
plished by  blazing  just  through  the  bark  into  the  live  wood  tissue. 
Where  trees  2 'inches  or  more  in  diameter  occur  along  a  line,  the 
required  blazes  will  not  be  omitted.  Where  trees  have  branches 
growing  to  the  ground,  the  blazes  will  be  omitted  unless  it  is  neces- 
sary to  remove  the  branches  to  permit  sighting. 

Lines  are  also  to  be  marked  by  cutting  away  enough  of  the  under- 
growth to  facilitate  correct  sighting  of  instruments.  Where  lines 
cross  deep  wooded  valleys,  by  sighting  over  the  tops,  the  usual 
blazing  of  trees  in  the  low  ground  when  accessible  will  be  performed, 
that  settlers  iriay  find  their  proper  limits  of  land  and  timber  without 
special  survey.  The  undergrowth  will  be  especially  well  cut  along 
all  lines  within  distances  of  5  chains  of  corner  monuments  and  within 
2  chains  of  arteries  of  travel,  to  enable  other  surveyors  and  settlers 
to  locate  the  survey  readily,  but  the  cutting  of  the  undergrowth 
may  be  omitted  in  deep  untraveled  rapines  unless  necessary  for 
accurate  sighting  or  measurement. 

Line  trees  and  blazing  will  be  marked  only  with  reference  to  the 
established  true  line,  and  where  lines  are  run  by  the  "random  and 
true  "  line  method,  the  marking  of  line  trees  and  the  blazing  will  be 
accomplished  by  returning  over  the  line  after  all  corrections  or  ad- 
justments to  the  final  line  are  definitely  known.  A  sufficient  number 
of  temporary  stakes  should  be  set  along  a  random  line  to  render  it 
generally  unnecessary  to  rerun  the  true  line  instrumentally  merely 
for  the  purpose  of  blazing  the  line  through  timber,  as  this  can  usually 
be  accomplished  by  properly  estimating  the  distance  from  the 
temporary  stakes,  but  intersections  with  line  trees  will  be  made  with 
precision,  and  distances  thereto  accurately  measured. 

SUMMARY   OF  OBJECTS  TO   BE   NOTED,  AND   SKETCHES. 

236.  The  field  notes  and  plat  of  a  survey  are  designed  to  furnish 
not  only  a  technical  record  of  the  procedure,  but  also  of  equal  im- 
portance a  report  upon  the  character  of  the  land,  soil  and  timber 
traversed  by  the  survey,  and  a  detailed  schedule  of  the  topographical 
features  along  every  line,  with  accurate  connections  showing  the 
relation  of  the  rectangular  surveys  to  other  surveys,  to  natural 
objects  and  to  improvements.  A  triple  purpose  is  thus  served:  (a) 
the  technical  procedure  is  made  a  matter  of  official  record;  (6) 


222  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

general  information  relating  to  a  region  is  gathered;  and,  (c)  the 
a" calls"  of  the  field  notes  and  the  representations  of  the  plat  in 
respect  to  objects  along  the  surveyed  lines  furnish  important  evi- 
dence by  which  the  locus  of  the  survey  becomes  practically  un- 
changeable as  contemplated  by  law. 

The  specimen  field  notes  and  plats  are  intended  to  standardize 
the  form  of  record,  and  many  special  matters  relating  to  these  sub- 
jects are  brought  together  in  Chapters  VIII  and  IX,  but  before 
concluding  the  special  questions  concerning  rectangular  surveys 
it  is  deemed  expedient  to  outline  the  technical  and  topographical 
features  which  are  to  be  carefully  observed  and  recorded  in  the 
field  during  the  progress  of  the  public-land  surveys: — 

1.  The  precise  course  and  length  of  every  line  run,  noting  all 
necessary  offsets  therefrom,  with  the  reason  for  making  them,  and 
method  employed. 

,-  2.  The  kind  and  diameter  of  all  bearing  trees,  with  the  course 
and  distance  of  the  same  from  their  respective  corners,  and  the 
markings;  all  bearing  objects  and  marks  thereon,  if  any;  and  the 
precise  relative  position  of  witness  corners  to  the  true  corners. 
,  3.  The  kind  of  material  of  which  corners  are  constructed,  their 
dimensions  and  markings,  depth  set  in  the  ground,  and  their 
accessories. 

4.  Trees  on  line.     The  name,  diameter  and  distance  on  line  to  all 
trees  which  it  intersects,  and  their  markings. 

5.  Intersections  by  line  of  land  objects.     The  distance  at  which 
the  line  intersects  the  boundary  lines  of  every  reservation,  town- 
site,  or  private  claim,  noting  the  exact  bearing  of  such  boundary 
lines,  and  the  precise  distance  to  the  nearest  boundary  corner;   the 
center  line  of  every  railroad,  canal,  ditch,  electric  transmission,  line, 
or  other  right-of-way  across  public  lands,  noting  the  width  of  the 
right-of-way  and  the  precise  bearing  of  the  center  line;  the  change 
from  one  character  of  land  to  another,  with  the  approximate  bearing 
of  the  line  of  demarcation,  and  the  estimated  height  in  feet  of  the 
'ascents  and  descents  over  the  principal  slopes  typifying  the  topog- 
raphy of  the  country  traversed,  with  the  direction  of  said  slopes; 
the  distance  to  and  the  direction  of  the  principal  ridges,  spurs, 
divides,  rim  rock,  precipitous  cliffs,  etc.;   the  distance  to  where  the 
line  enters  or  leaves  heavy  or  scattering  timber,  with  the  approxi- 
mate bearing  of  the  margin  of  all  heavy  timber,  and  the  distance 
to  where  the  line  enters  or  leaves  dense  undergrowth. 


SYSTEM  OF  RECTANGULAR  SURVEYS.  223 

6.  Intersections   by  line   of   water   objects.    All  unmeandered 
rivers,  creeks  and  smaller  water-courses  which  the  line  crosses;  the 
distance  measured  on  the  true  line  to  the  center  of  the  same  in  the 
case  of  the  smaller  streams,  and  to  both  banks  in  the  case  of  the 
larger  streams,  the  course  downstream  at  points  of  intersection,  and 
their  widths  on  line,  if  only  the  center  is  noted.     All  intermittent 
water-courses,  such  as  ravines,  gulches,  arroyos,  draws,  dry-drains,  etc. 

7.  The  land's  surface;  whether  level,  rolling,  broken,  hilly  or 
mountainous. 

8.  The  soil;  whether  rocky,  stony,  gravelly,  sandy,  loam,  clay, 
etc.,  and  also  whether  first,  second,  third  or  fourth  rate. 

9.  Timber;  the  several  kinds  of  timber  and  undergrowth,  in  the 
order  in  which  they  predominate. 

10.  Bottom  lands  to  be  described  as  upland  or  swamp  and  over- 
flowed, as  contradistinguished  under  the  law,  noting  the  extent  and 
approximate  position  of  the  latter,  and  depth  of  overflow  at  sea- 
sonal periods.     The  segregation  of  lands  fit  for  cultivation  without 
artificial  drainage,  from  the  swamp  and  overflowed  lands,  where  the 
latter  are  subject  to  selection  by  the  States,  is  always  accomplished 
by  legal  subdivision,  and  any  smallest  legal  subdivision  is  classified 
as  all  upland  or  all  swamp  and  overflowed  land  accordingly  as  more 
than  half  of  the  same  may  be  of  the  character  of  the  one  or  of  the 
other  class  of  lands;  bottom  lands  will  be  classified  with  special 
consideration  to  these  matters. 

11.  Springs  of  water,  whether  fresh,  saline,  or  mineral,  with  the 
course  of  the  stream  flowing  therefrom.     The  location  of  all  streams, 
springs,  or  water-holes,  which  because  of  their  environment  may 
be  deemed  to  be  of  value  in  connection  with  the  utilization  of  public 
grazing  lands,  and  which  may  be  designated  as  public  watering 
places,  will  be  specially  noted.  • 

12.  Lakes  and  ponds,  describing  their  banks,  tributaries  and  out- 
let, and  whether  the  water  is  pure  or  stagnant,  deep  or  shallow. 

13.  Improvements;  towns  and  villages;  post  offices;  Indian  occu- 
pancy; houses  or  cabins,  fields,  or  other  improvements,  with  owner's 
name;  mineral  claims;  mill-sites;  United  States  mineral  monuments, 
and  all  other  official  monuments  not  belonging  to  the  system  of 
rectangular  surveys;  will  be  located  by  bearing  and  distance  or  by 
intersecting  bearings  from  given  points. 

14.  Coal  banks  or  beds,  all  ore  bodies,  with  particular  description 
of  the  same  as  to  quality  and  extent;  all  mining  surface  improve- 


224  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

ments  and  underground  workings;  and  salt  licks.  All  reliable  in- 
formation that  can  be  obtained  respecting  these  objects,  whether 
they  be  on  the  line  or  not,  will  appear  in  the  general  description. 

15.  Roads  and  trails,  with  their  directions,  whence  and  whither. 

16.  Rapids,  cataracts,  cascades,  or  falls  of  water,  in  their  approxi- 
mate position  and  estimated  height  of  their  fall  in  feet. 

17.  Stone  quarries  and  ledges  of  rocks,  with  the  kind  of  stone  they 
afford. 

18.  Natural  curiosities,  petrifactions,  fossils,  organic  remains,  etc.; 
also  all  archaeological  remains,  such  as  cliff  dwellings,  mounds, 
fortifications,  or  objects  of  like  nature. 

19.  The  general  average  of  the  magnetic  declination  in  the  town- 
ship, with  maximum  known  range  of  local  attraction  and  other 
variations,  will  be  stated  in  the  general  description,  and  the  general 
average  for  the  township,  subject  to  local  attraction,  will  be  shown 
upon  the  plat. 

20.  General  description. — The  above  information  will  be  summar- 
ized by  townships  in  a  general  description  which  will  be  made  the 
concluding  part  of  the  field  notes  of  every  survey.    The  general 
description  will  be  made  to  embrace  many  more  comprehensive  de- 
tails in  regard  to  the  characteristics  of  the  region  than  is  feasible  to 
cover  as  an  intimate  part  of  the  technical  record  of  the  survey,  as 
follows: — 

Land. — A  general  outline  of  the  drainage  and  topographical  fea- 
tures of  the  township  and  approximate  range  of  elevation  above  sea 
level. 

Soil. — The  prevailing  and  characteristic  soil  types.  (See  special 
reference  to  soil  classification,  Chap.  VII.) 

Timber. — The  predominant  forest  species,  age,  size,  condition,  etc. 

Evidence  of  mineral. — All  known  bodies  of  mineral,  and  lands 
whose  formation  suggests  mineral-bearing  characteristics,  especially 
with  reference  to  lands  of  volcanic  or  igneous  origin,  will  be  listed 
by  appropriate  legal  subdivision,  with  brief  description  of  the  min- 
eral indications.  On  the  other  hand,  if  the  surveyor  finds  no  ap- 
parent indication  of  mineral  deposits,  a  report  to  that  effect  will  be 
embodied  in  the  general  description. 

Watering  places. — The  areas  embracing  all  streams,  springs,  or 
water  holes  as* may  be  of  special  value  as  public  watering  places, 
in  connection  with  the  utilization  of  public  grazing  lands,  will  be 
listed  by  appropriate  legal  subdivision,  with  brief  description  of  the 
nature  of  such  water  supply. 


SYSTEM   OF  RECTANGULAR   SURVEYS.  225 

Settlement. — The  extent  of  the  settlement  at  the  time  of  the  survey. 

Industry. — The  industrial  possibilities  of  the  township,  especially 
as  to  the  adaptability  of  the  region  to  agricultural  pursuits,  stock 
raising,  lumbering,  mining,  or  other  profitable  enterprise. 

Special. — All  exceptional  steps  in  the  technical  process  of  the 
survey,  and  other  special  matters  required  in  paragraphs  Nos.  1  to 
19,  inclusive,  of  the  above  summary,  not  otherwise  suitably  recorded 
will  be  reported  in  the  general  description. 

In  addition  to  the  field  notes  the  surveyors  are  required  to  prepare, 
as  the  work  progresses,  an  outline  diagram  showing  the  course  and 
length  of  all  established  lines  with  connections,  and  a  topographical 
sketch  embracing  all  features  usually  shown  upon  the  completed 
official  township  plat.  These  maps  will  be  made -to  scale,  drawn  in 
pencil  only,  if  desired,  and  will  be  kept  up  with  the  progress  of  the 
field  work.  The  interiors  of  the  sections  will  be  fully  completed; 
the  topographical  features  will  be  sketched  with  care  while  in  the 
view  of  the  surveyor,  and  the  position  within  the  section  of  the 
various  details  which  are  to  be  shown  on  the  completed  plat  will  be 
located  with  an  accuracy  commensurate  with  their  relative  impor- 
tance. The  design  of  the  specimen  township  plat  will  be  followed 
closely  in  the  preparation  of  the  outline  diagram  and  topographical 
sketch  plat,  except  that  it  will  generally  be  desirable  to  employ 
a  separate  sheet  for  each  of  the  two  purposes.  These  maps  will 
then  form  the  basis  of  the  official  plat,  the  ultimate  purpose  of 
which  is  a  true  and  complete  graphic  representation  of  the  public 
lands  surveyed. 


CHAPTER  IV. 
CORNER  MONUMENTS. 

THE   LEGAL   SIGNIFICANCE   OF   A   CORNER   MONUMENT. 

237.  It  is  one  of  the  fundamental  principles  of  the  surveying  laws 
that  absolute  permanency  be  attached  to  the  public-land  surveys 
when  the  lines  have  been  officially  established.  The  " survey  "  em- 
braces certain  definite  technical  procedure,  heretofore  described, 
also  the  marking  of  certain  fixed  points,  as  will  be  described  in  this 
chapter,  though  the  establishment  of  a  survey  may  not  be  termed 
" completed"  until  the  field  notes  and  plat  and  every  detail  of  the 
technical  operation  constituting  the  survey  have  been  finally  ac- 
cepted by  the  Commissioner  of  the  General  Land  Office,  all  as  con- 
templated by  law.  The  law  provides  that  the  original  corners 
established  during  the  process  of  the  survey  shall  forever  remain 
fixed  in  position,  even  to  disregarding  technical  errors  in  the  execu- 
tion of  the  survey — where  discrepancies  may  have  passed  undetected 
prior  to  the  acceptance  of  the  survey  and  the  opening  of  the  lands 
to  entry — and,  as  an  aid  to  the  matter  of  permanency,  the  Congress 
provides  for  the  purchase  of  durable  material  for  the  corner  monu- 
ments, also  a  penalty  for  the  defacing  of  any  marks  relating  to  the 
locus  of  the  survey.  If  it  were  possible  to  carry  out  the  full  intent 
of  the  surveying  laws  in  regard  to  the  aforementioned  particulars, 
the  most  intricate  of  all  technical  and  legal  problems  relating  to  sur- 
veys— the  questions  pertaining  to  the  reestablishmont  of  lost  cor- 
ners— would  be  avoided. 

The  courts  attach  major  importance  to  authentic  evidence  relating 
to  the  original  position  of  an  official  corner  monument,  such  evidence 
being  given  far  greater  weight  than  the  technical  record  relating  to 
bearings  and  lengths  of  lines,  and  it  is  assumed  in  the  first  instance 
that  the  original  corners  shall  serve  every  necessary  purpose  for  the 
identification  of  the  survey  delineated  upon  the  official  approved 
plat,  and  of  the  lands  which  have  passed  into  private  ownership. 
The  legal  significance  of  the  original  monuments,  as  thus  briefly 
outlined,  makes  it  mandatory  upon  the  surveyor  to  exercise  con- 

227 


228  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

stant  diligence  in  the  workmanlike  construction  of  lasting  corners, 
and  alertness  in  skillfully  connecting  the  same  with  natural  objects 
or  improvements,  to  the  end  that  the  greatest  possible  permanency 
may  be  secured  for  the  public-land  surveys. 

238.  Accordingly,  if  a  surveyor  is  called  upon  to  alter  the  con- 
dition of  a  previously  established  point,  the  utmost  regard  should 
be  shown  for  the  evidence  of  the  original  location  of  the  monument, 
and  the  corner  will  be  carefully  reconstructed  by  such  additional 
means  as  may  be  appropriate,  without  destroying  the  evidence  which 
served  to  identify  its  legal  position.    A  complete  record  will  be  kept 
of  the  description  of  the  old  monument  as  identified,  and  all  altera- 
tions and  additions  thereto. 

239.  Regulation  monuments  are  employed  to  mark  permanently 
the  position  of  the  quarter-section,  section,  township  and  meander 
corners,  appropriate  to  the  subdivision  of  the  public  lands,  as  de- 
scribed in  Chapter  III;  also  at  such  sixteenth-section  corners  as  the 
requirements  of  the  written  special  instructions  or  the  exigencies  of 
the  survey  of  fractional  sections  may  demand;  also  at  all  angle  points 
along  an  irregular  boundary  line,  and  at  intermediate  intervals  of 
40  and  80  chains  along  such  limiting  boundary.    A  more  extended 
discussion  of  the  subject  of  "angle  points"  and  other  monuments  to 
be  established  upon  irregular  boundaries  will  be  found  in  Chapter  VII. 

240.  The  position  of  every  corner  monument  will  be  ' '  evidenced  " 
by  the  best  of  such  accessories  as  may  be  available,  and  where  the 
corner  point  itself  can  not   be  marked  in  the  usual  manner  an 
appropriate  "witness  corner"    will  be    established.    A    "witness 
meander  corner"  will  be  established  upon  secure  ground  wherever 
the  intersection  of  a  surveyed  line  with  the  mean  high-water  ele- 
vation of  a  meanderable  body  of  water  falls  at  a  point  where  the 
monument  would  be  liable  to  destruction. 

241.  The  field  notes  relating  to  the  establishment  of  a  corner 
monument  will  be  introduced  into  the  technical  record  of  the  survey 
at  the  logical  place  in  the  record  where  the  true  position  for  the 
corner  is  indicated  as  having  been  attained.     The  record  of  the 

.  monument  itself  will  embrace  a  description  of: 

(a)  The  corner  material,  including  its  dimensions,  in  the  order 
of  length  and  diameter  of  an  iron  post;  or  length,  width  and  breadth 
of  a  stone;  or  the  breast  height  diameter  of  a  tree;  (6)  the  depth 
set  in  the  ground,  with  mention  of  additional  support  if  any; 
(c)  the  significance  of  its  position;  (d)  the  markings  upon  the  monu- 


CORNER    MONUMENTS.  229 

ment;  and  (e)  the  nature  of  the  accessories,  including  character, 
size,  position  and  markings. 

CORNER  MATERIAL. 

24:2.  The  General  Land  Office  has  adopted  a  model  iron  post  for 
monumenting  the  public-land  surveys,  which  will  be  generally 
used  unless  exceptional  circumstances  warrant  a  departure  from 
this  rule.  This  practice  is  deemed  so  important  that  the  surveyor 
is  not  authorized  to  exercise  an  option  in  the  matter,  but  he  may 
refer  the  question  to  the  proper  supervising  officer,  who  may  grant 
authority  for  the  use  of  other  suitable  material,  provided  the  reasons 
for  departing  from  the  general  rule  are  sufficient,  in  which  case  a 
brief  statement  of  the  facts  will  be  given  in  the  field  notes,  in  the 
form  of  an  explanation  as  to  why  the  model  iron  posts  were  not 
employed. 

The  model  iron  post  is  made  from  commercial  iron  pipe,  from  1  to 
3  inches  in  diameter,  which  is  cut  into  lengths  of  about  36  inches; 
one  end  of  the  pipe  is  split  for  a  distance  of  about  4  or  5  inches,  and 
the  two  halves  are  spread  (when  heated)  to  form  flanges  or  foot  plates, 
at  right  angles  to  the  axis  of  the  pipe;  a  brass  cap  is  securely  riveted 
to  the  opposite  end  of  the  pipe;  and  finally  the  pipe  is  filled  with 
concrete.  Unless  otherwise  provided  in  the  written  special  instruc- 
tions, the  iron  posts  will  be  employed  as  follows:  3-inch,  for  standard 
and  closing  township  corners,  corners  of  one,  two  or  four  townships, 
and  as  required  for  mile  corners  and  angle  points  of  special  bound- 
ary surveys;  2-inch,  for  standard  and  closing  section  corners,  and 
corners  of  one,  two  or  four  sections;  and,  1-inch,  for  quarter-sec- 
tion and  meander  corners,  and  as  required  for  miscellaneous  angle 
points,  sixteenth-section  corners  and  corners  of  special  tract  surveys. 
All  witness  corners  are  to  be  of  the  same  size  as  wouitl  be  used  for 
the  true  corner. 

243.  The  caps  of  the  iron  posts  are  to  be  suitably  and  plainly 
marked  with  steel  dies  at  the  time  when  used;  the  posts  will  be 
set  in  the  ground  about  three-fourths  of  their  length;  and  earth  and 
stone,  if  the  latter  is  at  hand,  will  be  tamped  into  the  excavation 
to  give  the  post  a  solid  anchorage. 

244.  Durable  native  stone  may  be  substituted  for  the  model  iron 
post,  if  the  procedure  has  been  duly  authorized,  but  no  stone  will 
be  used  which  measures  less  than  20  inches  in  length,  or  less  than 
5  inches  in  either  of  its  minor  dimensions,  or  less  than  1,000  cubic 
inches  in  volume.     A  stone  should  always  be  selected  with  regard 


230  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

to  its  durability  when  exposed  to  the  usual  weathering  influences. 
Stone  will  not  be  used  as  a  corner  monument  where  its  position  falls 
among  large  quantities  of  loose  surface  stone  or  slide  rock. 

245.  A  stone  will  be  suitably  and  legibly  marked  with  a  steel 
chisel  or  punch  with   such  letters,  figures,  grooves  or  notches,  as 
may  be  required,  and  will  be  set  firmly  in  the  ground  about  three- 
fourths  of  its  length . 

246.  Both  iron  post  and  stone  monuments  will  always  be  set 
the  usual  depth  in  the  ground  unless  it  is  impossible  to  complete 
the  excavation,  in  which  case  the  monument  will  be  planted  as 
deep  as  conditions  will  permit,  and  the  necessary  support  will  be 
secured  by  a  stone  mound. 

247.  Where  the  corner  point  falls  upon  solid  surface  rock,  pre- 
venting excavation,  a  cross  ( X )  will  be  cut  at  the  exact  corner  point, 
and,  if  feasible,  the  monument  will  be  erected  in  the  same  position, 
supported  by  a  large  stone  mound  of  broad  base,  so  well  constructed 
that  it  will  possess  thorough  stability. 

248.  Where  the  corner  point  falls  exactly  at  the  position  occupied 
by  a  sound  living  tree,  which  is  too  large  to  be  removed,  the  tree 
will  be  appropriately  marked  for  the  corner. 

WITNESS  CORNERS. 

249.  Where  the  true  point  for  a  corner  falls  within  a  roadway  in 
such  a  place  as  to  interfere  with  travel,  a  marked  ( X )  stone  will  be 
deposited  in  the  ground  at  the  true  corner  point  and  a  witness  corner 
will  be  established  at  some  suitable  point,  preferably  on  a  surveyed 
line,  outside  of  the  roadway. 

250.  Where  the  true  point  for  a  corner  falls  upon  insecure  ground, 
or  in  an  inaccessible  place,  such  as  within  an  immeandered  stream, 
lake  or  pond,  or  in  a  marsh,  or  upon  a  precipitous  elope  or  cliff,  a 
witness  corner  will  be  established  at  some  suitable  point,  preferably 
on  a  surveyed  line,  where  the  monument  may  be  permanently 
constructed. 

251.  The  surveyor  will  be  expected  to  exercise  his  best  judgment 
in  selecting  the  position  for  a  witness  corner,  with  a  view  to  afford- 
ing a  definite  and  convenient  connection  from  the  witness  corner  to 
the  true  point  for  the  monument,  for  use  in  subsequent  surveys  to 
recover  the  legal  position  of  the  true  corner.    Extra  effort  will  be 
exerted  to  accomplish  the  permanent  establishment  of  a  monument 
at  its  true  corner  point,  wherever  this  is  feasible,  in  order  to  avoid 
as  much  as  possible  the  confusion  to  settlers  and  others  caused  by 
witness  corners. 


CORNER   MONUMENTS.  231 

252.  Only  one  witness  corner  will  be  established  in  each  instance, 
and  the  same  will  be  placed  upon  any  one  of  the  surveyed  lines  lead- 
ing to  a  corner,  if  a  suitable  place,  within  a  distance  of  10  chains,  is 
available,  but  if  there  is  no  secure  place  to  be  found  on  a  surveyed 
line  within  the  stated  limiting  distance,  the  witness  corner  may  be 
located  in  any  direction  within  a  distance  of  5  chains.    On  the  other 
hand,  if  there  is  no  suitable  place  within  the  latter  radius,  one  or 
more  legal  subdivisions  will  be  eliminated  from  the  survey  as  pro- 
vided in  Chapter  VII. 

253.  All  of  the  lines  of  a  survey  will  be  completed  in  the  regular 
manner,  if  the  true  point  for  a  corner  is  accessible,  but  where  the 
true  point  can  not  be  attained,  a  line  connecting  therewith  may  be 
returned  as  surveyed  if  the  same  has  been  completed  by  the  pro- 
jection and  measurement  of  a  suitable  offset  or  traverse,  resulting 
in  a  closed  figure  which  approaches  the  true  point  for  a  monument 
within  the  limit  prescribed  for  the  establishment  of  witness  corners. 

254.  The  field  notes  will  show  every  detail  of  the  relation  of  a 
witness  corner  to  the  true  point  for  a  monument,  and  the  direct  con- 
necting course  and  distance  will  be  shown  upon  the  plat  of  the  survey. 

MARKING  CORNERS. 

255.  All  classes  of  corner  monuments  are  to  be  marked  in  accord- 
ance with  a  system  hereinafter  described  which  has  been  devised  to 
furnish  a  ready  identification  of  the  character  and  position  of  the 
monument  which  bears  the  marks.    Capital  letters  and  Arabic  figures 
are  employed  to  mark  iron  post  and  tree  comers,  while  upon  stone 
corners  certain  additional  marks  termed  "notches'*  and  "grooves'* 
are  employed  to  convey  the  same  information,  but  to  lessen  the  labor 
incident  to  the  marking  process.    The  letters  and  figures  upon  a 
monument  are  designed  to  relate  to  the  township,  »ange  and  sec- 
tion to  which  the  corner  belongs;  the  notches  and  grooves  upon  a 
stone  monument  relate — in  the  case  of  an  exterior  corner — to  the 
normal  number  of  miles  from  the  monument  to  the  adjoining  town- 
ship corners,  and — in  the  case  of  a  subdi visional  corner — to  the  nor- 
mal number  of  miles  from  the  monument  to  the  township  boundary 
lines,  as  hereinafter  described,  thus  furnishing  the  means  of  ascer- 
taining the  appropriate  section  numbers. 

256.  All  markings  should  be  accomplished  neatly,  distinctly  and 
durably;   and  the  marks  are  to  be  carefully  arranged.    An  assort- 
ment of  steel  dies,  chisels,  punches  and  timber  scribes,  in  perfect 
condition  for  use,  should  always  be  at  hand. 


232 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


257.  A  witness  corner  and  its  accessories  will  be  constructed  and 
marked  similarly  to  a  regular  corner  for  which  it  stands,  with  the 
additional  letters  **W  C"  to  signify  " witness  corner." 

258.  The  following  schedule  is  an  index  of  the  ordinary  markings 
common  to  all  classes  of  corners  and  accessories: — 


Marks. 

To  indicate. 

Marks. 

To  indicate. 

AMC 

Auxiliary  meander  cor- 

R 

Range. 

ner. 

S 

Section. 

AP 

Angle  point. 

S 

South. 

BO 

Bearing  object. 

sc 

Standard  corner. 

BT 

Bearing  tree. 

SE 

Southeast. 

C 

Center. 

SMC 

Special  meander  corner. 

CC 

Closing  corner. 

SW 

Southwest. 

E 

East. 

T 

Township. 

M 

Mile. 

TR 

Tract. 

MC 

Meander  corner. 

W 

West. 

N 

North. 

we 

Witness  corner. 

NE 

Northeast. 

WP 

Witness  point. 

NW 

Northwest. 

i 

Quarter  section. 

PL 

Public     land      (unsur- 

A 

Sixteenth  section. 

veyed). 

MARES  ON  IRON  POST  MONUMENTS. 

259.  The  markings  upon  the  brass  cap  of  an  iron  post  should  always 
be  made  to  read  from  the  south  side  of  the  monument,  and  all  iron 
posts  will  be  marked  with  the  year  number  at  the  date  when  estab- 
lished. 

260.  Standard  township  corners  are  to  be  marked  "S  C"  and  the 
township  on  the  north  half,  and  the  ranges  and  sections  in  the  proper 
quadrants;  as  for  example: 

SC 

T25  N 

RITE  I  RISE 
S36[S3I 

1916 

261.  Closing  township  corners  are  to  be  marked  "C  C  "  on  the  half 
from  which  the  closing  line  approaches  the  monument,  with  the 
township  (or  range)  on  the  same  half,  and  the  ranges  (or  townships) 
and  sections  in  the  proper  quadrants;   also  (as  far  as  known  at  the 
time)  the  township,  range  and  section,  or  the  initials  or  abbrevia- 


CORNER    MONUMENTS. 


233 


tion  of  the  State,  reservation,  grant  or  private  claim,  upon  which 
the  township  exterior  closes;  as  for  example: 


T25N   RI7E 
S36 


SI 
RITE 


S6 
RISE 


T24  N 
CC 
1916 


UTAH 


262.  Corners  common  to  four  townships  are  to  be  marked  with  the 
townships  on  the  north  and  south  halves,  the  ranges  on  the  east  and 
west  halves,  and  the  sections  in  the  four  quadrants;  as  for  example: 


T23N 


R  17  E 
S36 


RISE 
S3I 


SI      56 

T22  N 

1916 

263.  Corners  common  to  two  townships  only  are  to  be  marked  with 
the  township  (or  range)  common  to  both  on  the  proper  half,  and  the 
ranges  (or  townships)  and  sections  in  the  proper  quadrants;  also  (as 
far  as  known  at  the  time)  the  township,  range  and  section  upon  the 
opposite  half ;  as  for  example: 

TI4S 


T3N 

R7W 

S36 

T2  N 

R6W 

S  1 

S6 

T2N 

R7  W 
S  36 

R6W 
S3I 

1916 


TI5S  R7  W  SI 
1916 


264.  Corners  referring  to  one  township  only  are  to  be  marked  with 
the  township,  range  and  section  in  the  particular  quadrant  which  is 
concerned;  also  (as  far  as  known  at  the  time)  the  township,  range 
and  section  upon  the  opposite  part;  as  for  example: 


T54N  R43E 
SI 
1916 


55465°— 19- 


-16 


234  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

265.  Standard  section  corners  are  to  be  marked  "S  C"  and  the 
township  and  range  on  the  north  half,  and  the  sections  in  the  proper 
quadrants;  as  for  example: 

SC 

T25  N  I  RI7E 
S  35     S  36 


1916 

266.  Closing  section  corners  are  to  be  marked  "C  C"  and  the 
township  and  range  on  the  half  from  which  the  closing  line  approaches 
the  monument,  and  the  sections  in  the  proper  quadrants;  also  (as 
far  as  known  at  the  time)  the  township,  range  and  section,  or  the 
initials  or  abbreviation  of  the  State,  reservation,  grant  or  private 
claim,  upon  which  the  section  line  closes,  with  the  exception  that 
in  the  case  of  an  interior  closing  section  corner,  the  township  and 
range  numbers  will  not  be  repeated;  as  for  example: 

T25N   RI7E  TR48 

S  35 


__  S  26    S  25 

TI2  N      R5W 
T  24  N  I  R  17  E  Cc 

1916  '916 

267.  Corners  common  to  four  sections  are  to  be  marked:  (a)  On 
an  exterior,  with  the  township  (or  range)  common  to  the  adjoining 
townships,  the  ranges  (or  townships)  upon  the  opposite  sides  of  the 
exterior,  and  the  sections;  and  (b)  a  subdivisional  corner,  with  the 
township,  range  and  sections;  all  appropriately  set  forth  as  follows: 

T25N  T26N    R  17  E  T25N    RI7E 


ft  17  El 
S  12 


RI8E  535    S36  523    524 

S7 


52    SI  526     S  25 


S 13    518  T25N  1916 

1316 
1916 

268.  Section  corners  common  to  two  sections  only  are  to  be  marked 
with  the  township  and  range  on  the  half  facing  the  sections  to  which 
the  corner  belongs,  and  the  sections  in  the  proper  quadrants;  also 
(as  far  as  known  at  the  time)  the  township,  range  and  section  upon 


CORNER   MONUMENTS.  235 

the  opposite  half,  except  that  in  the  case  of  an  interior  corner,  the 
township  and  range  numbers  will  not  be  repeated;  as  for  example: 


TI4S  T27N 

S3I 


FM7W  TI4SIR20W 


S32  S  10     Sll 


T26N    RI7W  S  14 

S  6  1916 

1916 

269.  Section  corners  referring  to  one  section  only  are  to  be  marked 
with  the  township,  range  and  section  in  the  particular  quadrant 
which  is  concerned;  also  (if  known  at  the  time)  the  section  upon 
the  opposite  part;  as  for  example: 

T27NI  S28 

RI6W 
S  17  I 

S20 
1916 

270.  Standard  quarter-section  corners  are  to  be  marked  "S  C 
and  the  section,  all  on  the  north  half;  as  for  example: 

SC 
is  36 


1916 

271.  Quarter-section  corners  of  maximum  control  are  to  be  marked 
(a)  on  a  meridional  line,  "J"  on  the  north,  and  the  sections  on  the 
east  and  west  halves;  and,  (b)  on  a  latitudinal  line,  "J"  on  the 
west,  and  the  sections  on  the  north  and  south  halves;  as  for  example: 


S,3|s,8 

1916 

272.  Quarter-section  corners  of  minimum  control  are  to  be  marked 
"}"  and  the  section,  all  on  the  half  toward  the  particular  section 
which  is  concerned;  as  for  example: 


1916 


236 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


273.  Meander  corners  are  to  be  marked  "M  C  "  on  the  half  toward 
the  meanderable  body  of  water,  and  the  additional  marks  (a)  on  a 
standard  parallel  or  other  line  controlling  surveys  to  one  side  only, 
with  the  township,  range  and  section  toward  the  surveyed  land; 
(6)  on  an  exterior,  with  the  township  (or  range)  common  to  the 
adjoining  townships,  the  ranges  (or  townships)  upon  the  opposite 
sides  of  the  exterior,  and  the  sections;  and,  (c)  on  a  subdi visional 
line,  with  the  township,  range  and  sections;  all  appropriately  set 
forth  as  follows: 


7 


/T25N 
/RI7E 
^533 


1916 


T24N 

RI7E     RISE 
SI3     SI8 


MC 


MC 


MC 


T25N    RI7E 
1916 


MC 


274.  The  interior  quarter-section  and  all  sixteenth-section  corners, 
when  required  by  the  written  special  instructions,  are  to  be  marked 
in  accordance  with  the  scheme  shown  in  the  following  diagram: 


CORNER   MONUMENTS. 


237 


s. 

1916 


.    525 

pi 

16  536 

^536 

1916 

1916 

.     i 

1 

\                     ' 

I 

1 

1 

t 

1 

N 

*                             NW&S36                                ? 

NE,iS36                               N 

c  7| 

1 

N^|S3< 
1916 

1916 
.19 

T 

1 

| 

l 

t 

f 

1 

l 

' 

cW|^                           CJ  S36 

cE*c 

, 

S  36                                   1916 

S36 

1916 

1916 

1 

1 

1 

1 

4 

t 

s 

e  oc 

336     ---       SW£S36                          SjT?s36 

5E^  S36                        SJ 

*, 

9OO 

19 

6                                   l916                                  '6C 

13.6 

& 

1916 

i 

1 

i 

t 

i 

1 

t 

j 

i 

L  .     wi;536 

i  S3^ 

275.  Sixteenth-section  corners  of  minimum  control  are  to  be  marked 
with  a  key  letter  (N,  E,  S  or  W),  to  indicate  the  position  of  the 
monument,  and  "A"  and  the  section,  all  on  the  half  toward  the 
particular  section  which  is  concerned;  as  for  example: 


r 

i 

i 

2 

< 

L 

\/ 

t 

.  ] 

S36 


1916 


Key 


238 


MANUAL,  OF  SURVEYING  INSTRUCTIONS. 


276.  Special  meander  corners  are  to  be  marked  in  accordance  with 
the  following  scheme : 

Key  letters  (N,  E,  S,  W  or  C)  will  be  used  in  pairs  to  indicate 
the  position  of  the  subdivision  -  of  -  section  line. 
, —  w — c— E — , 


1 

i 

i 

u 

/  —  c 

:  —  £ 

:J 

Key 

The  marks  "S  M  C"  will  be  placed  on  the  half  toward  the 
derable  body  of  water,  and  the  section  on  the  opposite  half, 
example: 

SMC  SMC  E 

w 


mean- 
as  for 


S    30 

W 

(916 

44 

30/SMC 
1916 


S|30 


SMC 
1916 

SMC/  S 
S/ S 

/    30 
1916 


277.  Auxiliary  meander  corners  will  be  marked  "A  M  C"  and  the 
township,  range  and  section;  as  for  example: 

AMC 

TB4N-R37W 
S29 
1916 

278.  Closing  subdivision  -of -section  corners  are  to  be  marked  in 
accordance  with  the  following  scheme: 

Key  letters  (N,  E,  S,  W  or  C)  will  be  used  in  pairs  to  indicate 
the  position  of  the  subdivision  -  of  -  section  line. 


r 

N 

V—  ( 

:  —  t 

'"I 

! 

1 

1 

c 

1 

ti 

v—c 

K< 

;—  E 

3V 

:_J 

CORNER   MONUMENTS. 


239 


The  marks  "C  C"  and  the  section  will  be  placed  on  the  half  from 
which  the  closing  line  approaches  the  monument. 
(The  marks  "B  I  R"  indicate  "Blackfeet  Indian  Reservation.") 


279.  Markings  for  miscellaneous  angle  points  along  irregular 
boundaries: 


T27N/ 

R!7VV\ 

1916 

AP 

TI2S   R90W 
S  33 

1916 


For  "angle  point  No.  4  "  on  the 
boundary  of  the  "Blackfeet  In- 
dian Reservation,"  falling  on 
surveyed  land. 

For  "angle  point"  on  the  south 
boundary  of  section  33,  super- 
seding an  old  standard  corner  on 
a  defective  line,  not  subject  to 
rectification. 

For  "angle  point  No.  2"  on 
the  boundary  of  a  private  claim 
("Tract  No.  37  ")  falling  on  sur- 
veyed land. 

For  "angle  point  No.  12"  on 
a  reestablished  meander  line;  the 
marks  "A  P"  and  the  serial 
number  will  be  placed  on  the 
half  toward  the  land  omitted 
from  the  original  survey. 


240  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

280.  Markings  for  intermediate  corners  along  irregular  boundaries: 

139  M  For  "139th  mile  corner"  on 

N  MEX  the  boundary  line  between  the 

TEXAS  States    of    "New   Mexico   and 

,916  Texas." 

For  "3d  mile  corner"  on  the 
boundary  of  the  "Blackfeet  In- 
dian Reservation,"  falling  on 
unsurveyed  land. 

T  25  N  ^or  l ' 13t^  m^e  corner  "  on  the 

R  17  w  boundary  of  the  "Blackfeet  In- 

\S25  dian    Reservation,"   falling   on 

19 16  surveyed  land. 

MARKS  ON  STONE  MONUMENTS. 

281.  Where  a  stone  monument  is  established  the  letters,  figures, 
and  grooves  will  be  cut  on  the  exposed  faces  or  sides  of  the  stone, 
but  not  on  its  top  or  end;  the  notches  will  be  cut  upon  the  exposed 
vertical  edges.    Grooves  are  employed  where  the  faces  of  a  stone 
are  oriented  to  the  cardinal  directions,  and  notches  where  the  vertical 
edges  are  turned  to  the  cardinal  points.    All  marks  will  be  made 
from  1  to  1J  inches  in  size,  and  will  be  plainly  and  permanently 
chiseled  into  the  stone. 

282.  Standard  township  corners  (oriented  with  the  faces  to  the 
cardinal  directions)  are  to  be  marked  "S  C"  on  the  north  face,  with 
the  township  on  the  same  face,  and  the  ranges  on  the  adjoining  faces; 
as  for  example: 

S  C  25  N  on  N., 

18  E    "    E.,  and 
17  E    "    W.  face. 

283.  Closing  township  corners  (oriented  with  the  faces  to  the 
cardinal  directions)  are  to  be  marked  "C  C  "  and  with  six  (or  fewer) 
grooves  on  the  face  from  which  the  closing  line  approaches  the 
monument — the  grooves  to  indicate  the  normal  number  of  miles 
(or  fractional  parts)  from  the  monument  to  the  adjoining  township 


CORNER   MONUMENTS.  241 

corner — with  the  township  (or  range)  on  the  same  face,  and  the 
ranges  (or  townships)  on  the  adjoining  faces;  also  the  initials  or 
abbreviation  of  the  State,  reservation,  grant  or  private  claim,  on 
the  face  toward  such  irregular  tract  as  may  be  closed  upon;  as  for 
example: 

20  N  on  N., 

C  C  120  W  and  5  grooves  (on  line  between  sections 
5  and  32)  on  E., 

19  N     on  S.,  and 
UTAH  "  W.  face. 

284.  Corners  common  to  four  townships  (oriented  with  the  edges  to 
the  cardinal  points)  are  to  be  marked  with  the  townships  on  the 
northeast  and  southwest  faces,  and  the  ranges  on  the  southeast  and 
northwest  faces;  as  for  example: 

23  N  on  NE., 
18  E   "   SE., 
22  N  "  SW.,  and 
17  E   "   NW.  face. 

285.  Corners  common  to  two  townships  only  (oriented  with  the 
faces  to  the  cardinal  directions)  are  to  be  marked  with  the  town- 
ship (or  range)  common  to  both  on  the  face  toward  the  townships, 
and  the  ranges  (or  townships)  on  the  adjoining  faces;  as  for  example: 

3  N  on  N., 
2  N  "   S.,  and 
7  W  "  W.  face. 

286.  Corners  referring  to  one  township  only  (oriented  with  the 
edges  to  the  cardinal  points)  are  to  be  marked  with  the  township 
and  range  on   the  face  toward    the  particular  township;  as  for 
example: 

23  N  7  W  on  NW.  face. 

287.  Standard  section  corners  (oriented  with  the  faces  to  the  car- 
dinal directions)  are  to  be  marked  "S  C"  on  the  north  face,  and 
with  from  one  to  five  grooves  on  the  east  and  west  faces,  the  grooves 


242  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

to  indicate,  respectively,  the  number  of  miles  from  the  monument  to 
the  adjoining  (regular)  township  corner;  as  for  example: 

S  C  on  N., 

1  groove  on  E.,  and 

5  grooves  on  W.  face  (standard  corner  of  sec- 
tions 35  and  36). 

288.  Closing  section  corners  (oriented  with  the  faces  to  the  cardinal 
directions)  are  to  be  marked  "C  C  "  and  with  from  one  to  six  grooves 
on  the  face  from  which  the  closing  line  approaches  the  monument, 
and  from  one  to  five  grooves  on  each  of  the  adjoining  faces — the 
grooves  to  indicate  the  number  of  miles  (or  fractional  parts)  from 
the  monument  to  each  of  the  three  (regular)  township  boundary 
lines  in  the  same  directions,   respectively — also  the  initials  or 
abbreviation  of  the  State,  reservation,  grant  or  private  claim,  on 
the  face  toward  such  irregular  tract  as  may  be  closed  upon;  as  for 

example: 

2  grooves  on  E., 

CCand6       "       "  S.,  and 

4  "  "  W.  face  (on  line  between  sec- 
tions 2  and  3  closing 
on  a  standard  par- 
allel). 

289.  Corners  common  to  four  sections  (oriented  with  the  edges  to 
the  cardinal  points)  are  to  b'e  marked  (a)  on  an  exterior,  with  from 
one  to  five  notches  each  on  two  opposite  edges,  north  and  south  on  a 
meridional  line,  and  east  and  west  on  a  latitudinal  line,  each  to 
indicate,  respectively,  the  number  of  miles  from  the  monument  to 
the  adjoining  (regular)  township  comer;  and  (6)  a  subdi visional 
corner,  with  from  one  to  five  notches  on  the  east  and  south  edges, 
each  to  indicate,  respectively,  the  number  of  miles  from  the  monu- 
ment to  the  (regular)  east  and  south  township  boundary  lines;  the 
subdivisional  section  corners  of  a  fractional  township  will  be  marked 
with  reference  to  the  theoretical  position  of  normal  east  and  south 
boundaries,  whether  surveyed  or  not;  as  for  example: 

2  notches  on  N.  and  4  notches  on  S.  edge  (for  corner  of  sec- 
tions 7, 12, 13  and  18  on  a  range  line). 

2  notches  on  E.  and  4  notches  on  W.  edge  (for  corner  of  sec- 
tions 2,  3,  34  and  35  on  a  township  line). 

2  notches  on  E.  and  4  notches  on  S.  edge  (for  corner  of  sec- 
tions 10,  11,  14  and  15  of  a  subdivisional  survey). 


CORNER   MONUMENTS.  243 

290.  Section  comers  common  to  tivo  sections  only  (oriented  with 
the  edges  to  the  cardinal  points)  are  to  be  marked  with  the  sections  on 
the  faces  toward  the  particular  sections  to  which  the  corner  belongs; 
as  for  example: 

S  13onSW.,  and 

S  12  "  NW.  face  (for  corner  of  sections  12  and  13  on  the  east 

boundary  of  a  township). 
S  11  on  NE.,  and 

5  10  "  NW.  face  (for  corner  of  sections  10  and  11  of  a  subdivi- 

sional  survey  running  north  from  the  mon- 
ument). 

291.  Section  corners  referring  to  one  section  only  (oriented  with 
the  edges  to  the  cardinal  points)  are  to  be  marked  with  the  section 
on  the  face  toward  the  particular  section  which  is  concerned;  as  for 
example: 

S  17  on  NW.  face  (for  southeast  corner  of  section  17). 

292.  Standard  quarter-section  corners  (oriented  with  the  faces  to 
the  cardinal  directions)  are  to  be  marked  "S  C  J"  on  the  north  face. 

293.  Quarter-section  corners  of  maximum  control  (oriented  with  the 
faces  to  the  cardinal  directions)  are  to  be  marked  (a)  on  a  meridional 
line,  "  J"  on  the  west  face;  and  (b)  on  a  latitudinal  line,  "  J"  on  the 
north  face. 

294.  Quarter-section  corners  of  minimum  control  (oriented  with  the 
faces  to  the  cardinal  directions)  are  to  be  marked  UJ"  and  the  sec- 
tion, all  on  the  face  toward  the  particular  section  which  is  con- 
cerned; as  for  example: 

1  S  4  on  S.  face  (for  quarter-section  corner  on  the  north  boundary 
of  section  4).  * 

295.  Meander  corners  (oriented  with  the  faces  to  the  cardinal 
directions)  are  to  be  marked  "M  C"  on  the  face  toward  the  mean- 
derable  body  of  water,  and  with  from  one  to  six  grooves  on  each  of 
the  other  faces,  each  to  indicate  the  number  of  miles  (or  fractional 
parts)  from  the  monument  to  the  (regular)  township  boundary  line 
in  the  same  direction,  respectively;  as  for  example: 

M  C  on  N., 

6  grooves  "  E., 

4      "        "  S.,  and 

6  "  "  W.  face  (for  meander  corner  of  fractional  sections 
13  and  18,  on  the  south  side  of  a  meander- 
able  body  of  water). 


244  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

296.  Special  and  auxiliary  meander  corners  (oriented  with  the  faces 
to  the  cardinal  directions)  are  to  be  marked  "S  M  C"  or  "A  M  C," 
as  the  case  may  be,  on  the  face  toward  the  meanderable  body  of 
water,  and  the  section  on  the  opposite  face;  as  for  example: 

S  M  C  on  N.,  and 

S  19      "  S.    face  (for  special  meander  corner  on  a  meridional 

subdivision-of-section  line  in  section  19, 

on  the  south  side  of  a  meanderable  body 

of  water). 
S  20     on  E.,  and 
A  M  C  "  W.  face  (for  auxiliary  meander  corner  in  section  20, 

on  the  east  side  of  a  meanderable  body  of 

water) . 

MARES  ON  TREE  MONUMENTS. 

297.  Where  the  true  point  for  a  corner  is  found  to  fall  in  the  posi- 
tion occupied  by  a  sound  living  tree,  which  is  too  large  to  be  removed, 
the  tree  will  be  made  the  monument.    A  tree  will  be  removed  if  it 
is  too  small  to  be  marked,  and  a  witness  corner  will  be  established 
in  preference  to  marking  an  unsound  tree,  if  the  latter  can  not  be 
removed. 

298.  The  species  of  the  tree  and  its  diameter,  breast  height,  will 
be  noted,  where  a  tree  is  to  be  made  a  monument,  and  the  appro- 
priate marks  will  be  made  upon  the  trunk  of  the  tree  immediately 
above  the  root  crown.    A  series  of  marks  to  be  made  upon  a  particu- 
lar side  of  a  tree  will  be  scribed  in  a  vertical  line  reading  downward. 

299.  In  the  case  of  certain  trees,  including  the  aspen,  beech  and 
locust  (smooth,  thin  and  permanently  barked  from  sapling  to  ma- 
turity), the  marks  may  be  made  preferably  by  scribing  well  into  the 
bark  and  cambium  (or  live  wood  tissue)  without  blazing;  the  marks 
thus  made  will  remain  and  be  visible  as  long  as  the  tree  is  sound; 
on  the  other  hand,  in  the  case  of  practically  all  rough  barked  trees, 
the  marks  should  be  scribed  into  a  smooth,  narrow,  vertical  "blaze, 
specially  prepared  by  removing  just  enough  of  the  outer  growth  to 
expose  a  flat  surface  of  the  live  wood  tissue  immediately  under- 
neath the  bark;  the  marks  thus  made  will  remain  as  long  as  the  tree 
is  sound,  but  the  blaze  and  marks  will  be  covered  by  a  gradual  over- 
growth, showing  an  outward  scar  for  many  years.     In  regions  sub- 
ject to  heavy  snowfall  it  is  desirable  to  make  a  small  additional 
blaze  at  a  height  of  6  or  8  feet  above  the  ground,  which  will  serve 
to  attract  attention  to  the  tree  during  the  winter  season.    The  ends 


CORNER   MONUMENTS.  245 

of  all  blazes  should  be  smoothed  off  gradually  without  making  a 
sharp  cut  into  the  cambium.  The  lower  end  of  the  blaze  upon 
which  the  marks  are  placed  should  be  about  6  inches  above  the  root 
crown,  and  its  length  should  be  just  sufficient  to  take  the  marks. 

The  practice  relating  to  the  manner  of  marking  trees,  as  above 
outlined,  is  designed  to  cause  the  least  possible  injury  to  the  tree, 
by  enabling  a  rapid  overgrowth;  also,  to  place  the  marks  in  a  position 
where  they  will  remain  on  the  stump  if  the  trunk  should  be  re- 
moved. Various  practices  have  obtained  in  the  past  in  different 
localities,  some  of  which  are  objectionable  by  causing  unnecessary 
injury  to  a  tree,  or  on  account  of  the  marks  being  placed  in  a  position 
where  there  is  danger  of  their  removal  with  the  trunk  in  case  the 
tree  is  cut  down. 

300.  The  above  theory  applies  equally  to  the  marking  of  bearing 
trees,  and  the  surveyor  is  advised,  when  making  retracements,  re- 
surveys,  etc.,  not  to  remove  the  overgrowth  on  a  tree  monument  or 
bearing  tree  unless  it  is  absolutely  necessary  to  do  so  in  order  to 
identify  positively  the  particular  tree.     In  the  case  of  trees  which 
have  been  blazed  before  marking,  the  number  of  rings  contained  in 
the  overgrowth  (or  its  equivalent  on  the  adjoining  section  of  the 
tree)  will  furnish  an  exact  count  of  the  number  of  years  (one  annual 
ring  for  each  growing  season)  from  the  date  of  original  marking  to 
the  date  when  uncovered.     After  an  old  blaze  has  been  uncovered, 
conditions  are  favorable  for  the  decaying  process  to  set  in,  and  the 
surveyor  should  adopt  additional  means  to  evidence  the  position 
of  the  corner. 

301.  Standard  township  corners  are  to  be  marked  "S  C"  and  the 
township  on  the  north  side,  and  the  ranges  and  sections  on  the  east 
and  west  sides;  as  for  example: 

SCT25N   onN., 
R  18  E  S  31  "  E.,  and 
R  17  E  S  36  "  W.  side. 

302.  Closing  township  corners  are  to  be  marked  "C  C"  and  the 
township  (or  range)  on  the  side  from  which  the  closing  line  ap- 
proaches the  monument,  and  the  ranges  (or  townships)  and  sections 
on  the  adjoining  sides;  also  the  initials  or  abbreviation  of  the  State, 
reservation,  grant  or  private  claim,  on  the  side  toward  any  irregular 
tract  which  may  be  closed  upon:  as  for  example: 

R  18  E  S  6  on  E., 
CCT24N  "  S.,  and 
R  17  E  S  1  "  W.  side. 


246  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

303.  Corners  common  to  four  townships  are  to  be  marked  with  the 
township  and  section  on  the  northeast  and  southwest  sides,  and  the 
range  and  section  on  the  southeast  and  northwest  sides;  as  for  ex- 
ample: 

T  23  N  S  31  on  NE., 

RISES    6  "  SE., 

T  22  NS    1   "  SW.,and 

R  17  E  S  36  "  NW.  side. 

304.  Cornel's  common  to  two  townships  only  are  to  be  marked  with 
the  township,  range  and  section  on  the  sides  toward  the  particular 
townships;  as  for  example: 

T2NR7WS    lonSW.,and 
T  3  N  R  7  W  S  36  "  NW.  side. 

305.  Corners  referring  to  one  township  only  are  to  be  marked  with 
the  township,  range,  and  section  on  the  side  toward  the  particular 
township  which  is  concerned ;  as  for  example : 

T  23  N  R  7  W  S  36  on  NW.  side. 

306.  Standard  section  corners  are  to  be  marked   "S  C"  and  the 
township  and  range  on  the  north  side,  and  the  sections  on  the  east 
and  west  sides;  as  for  example: 

S  C  T  25  N  R  17  E  on  N., 

S36    "E.,  and 
S35    "W.  side. 

307.  Closing  section  corners  are  to  be  marked  "C  C"  and  the 
township  and  range  on  the  side  from  which  the  closing  line  approaches 
the  monument,  and  the  sections  on  the  adjoining  sides;    also  the 
initials  or  abbreviation  of  the  State,  reservation,  grant  or  private 
claim  on  the  side  toward  any  irregular  tract  which  may  be  closed 

upon;  as  for  example: 

51  onE., 

CCT24NR17E  "   S.,  and 

52  "  W.  side. 

308.  Corners  common  to  four  sections  are  to  be  marked  (a)  on  an 
exterior,  with  the  township  (or  townships),  ranges  (or  range)  and 
sections;  and  (6)  a  subdi visional  corner,  with  the  township,  range 
and  section;  all  appropriately  set  forth  as  follows: 

T25NS    7onNE., 
RISES  18  "  SE., 
R17ES13  "  SW.,and 
S12  "  NW.  side. 


CORNER   MONUMENTS.  247 

T26NS36onNE., 
R17ES    1  "  SE., 
T25NS    2  "  SW.,  and 
S35  "  NW.  side. 

T  25  N  S  24  on  NE., 
R17ES25  "  SE., 

S26  "  SW.,  and 

S23  "  NW.  side. 

309.  Section  corners  common  to  two  sections  only  are  to  be  marked 
with  the  township  and  section  and  the  range  and  section  on  the 
sides  toward  the  particular  sections  to  which  the  corner  belongs; 
as  for  example : 

T14SS11  onNE.,  and 
R20WS10"NW.  side. 

310.  Section  corners  referring  to  one  section  only  are  to  be  marked 
with  the  township,  range  and  section  on  the  side  toward  the  par- 
ticular section  which  is  concerned;  as  for  example: 

T-27  N  E  16  W  S  17  on  NW.  side. 

311.  Standard  quarter-section  corners  are  to  be  marked  "S  G  J" 
and  the  section,  all  on  the  north  side;  as  for  example: 

S  C  i  S  36  on  N.  side. 

312.  Quarter-section  corners  of  maximum  control  are  to  be  marked 
(a)  on  a  meridional  line,  "|"  and  the  section  on  the  west  side,  and 
the  section  on  the  east  side;  and  (6)  on  a  latitudinal  line,  "J"  and 
the  section  on  the  north  side,  and  the  section  on  the  south  side;  as 
for  example : 

S  18  on  E.,  and 
JS13  "  W.  side. 
J  S  21  on  N.,  and 

S  28  "   S.  side. 

313.  Quarter-section  corners  of  minimum  control  are  to  be  marked 
"i"  and  the  section,  all  on  the  side  toward  the  particular  section 
which  is  concerned;  as  for  example: 

J  S  7  on  E.  side  (for  quarter-section  corner  on  the  west  boundary 
of  section  7). 

314.  Meander  corners  are  to  be  marked  "M  C"  on  the  side  toward 
the  meanderable  body  of  water,  and  the  additional  marks  (a)  on  a 
standard  parallel  or  other  line  controlling  surveys  to  one  side  only, 
with  the  township,  range  and  section  on  the  side  toward  the  sur- 


248  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

veyed  land;  (6)  on  an  exterior,  with  the  township  (or  range)  common 
to  the  adjoining  townships  on  the  side  opposite  the  meanderable 
body  of  water,  and  the  ranges  (or  townships)  and  the  sections  on 
the  adjoining  sides;  and,  (<,•)  on  a  subdivisional  line,  with  the  town- 
ship and  range  on  the  side  opposite  the  meanderable  body  of  water, 
and  the  sections  on  the  adjoining  sides;  as  for  example: 

M  C  on  E.,     and 

T  25  N  K  17  E  S  33    "    NW.  side  (for  meander  corner  on  a 

standard  parallel,  on  the 
west  side  of  a  meander- 
able  body  of  water). 
T  24  N  on  N., 
R  18  E  S  18   "    E., 

M  C   "    S.,  and 

R  17  E  S  13   "   W.  side  (for  meander  corner  on  a  range  line, 

on  the  north  side  of  a  meanderable 
body  of  water). 
T  23  N  S  35  on  N., 
M  C   "    E., 
T  22  N  S    2   "   S.,  and 

R  17  W   ' '   W.  side  (for  meander  corner  on  a  township 
line,  on  the  west  side  of  a  mean- 
derable body  of  water). 
•S  23  on  N., 
T  25  N  K  17  E   "   E., 

S  26   "   S.,.  and 

M  C   "   W.  side  (for  meander  corner  on  a  lati- 
tudinal  section   line,    on    the 
east    side    of    a    meanderable 
body  of  water). 
M  C  on  N., 
S    9   "   E., 
T  4  N  R  7  W   "   S.,  and 

S  8  "  W.  side  (for  meander  corner  on  a  meridional 
.section  line,  on  the  south  side  of 
a  meanderable  body  of  water). 

315.  Special  and  auxiliary  meander  corners  are  to  be  marked 
"S  M  C"  or  "AM  C",  as  the  case  may  be,  on  the  side  toward  the 
meanderable  body  of  water,  and  the  section  on  the  opposite  side; 
^ts  for  example: 


CORNER    MONUMENTS.  249 

S  M  C  on  E.,  and 

S  14       "   W.  side  (for  special  meander  corner  on  a  latitudinal 

subdivision-of -section  line  in  section  14, 

on  the  west  side  of  a  meanderable  body 

of  water). 
A  M  C  on  N.,  and 
S  9         "   S.    side  (for  auxiliary  meander  corner  in  section  9, 

on  the  south  side  of  a  meanderable  body 

of  water) . 

CORNER  ACCESSORIES. 

316.  The  purpose  of  a  corner  accessory  is  to  evidence  the  position 
of  the  original  monument.    A  connection  is  made  from  the  monu- 
ment to  fixed  natural  or  artificial  objects  in  its  immediate  vicinity, 
whereby  the  former  may  be  relocated  from  the  latter,  thus  in  the 
event  of  the  destruction  or  removal  of  the  corner  monument,  its 
original  position  may  be  identified  as  long  as  any  part  of  the  acces- 
sories remains  in  evidence.    The  accessories  consist  of  three  general 
classes,  one  or  more  of  which  are  to  be  employed  at  each  and  every 
corner   established   in  the  public-land  surveys,  preference  being 
given  to  the  same  in  the  order  of  their  permanency  conditional 
upon  the  character  of  the  ground  in  the  locality  of  the  monument, 
as  follows: 

(a)  Bearing  trees,  or  other  natural  objects  such  as  notable  cliffs 
and  boulders;  permanent  improvements;  and  memorials;  (6)  mound 
of  stone;  and  (c)  pits. 

317.  The  surveyor  can  not  perform  any  more  important  service 
in  connection  with  his  official  duties  than  to  employ  whatever 
means  may  be  necessary  permanently  and  accurately  to  evidence 
the  location  of  the  legal  corners  established  in  his  survey,  and  where 
the  usual  accessories,  or  combinations  of  the  same,  can  not  be  em- 
ployed, such  other  means  should  be  adopted  as  will  best  serve  the 
purpose. 

318.  The  accessories  for  witness  corners  will  be  the  same  as  though 
the  corner  were  established  at  its  true  point,  but  the  marks  upon 
the  bearing  trees  or  other  objects  will  be  preceded  by  the  letters 
"W  C",  and  the  section  number  will  be  made  to  agree  with  the 
section  in  which  the  tree  or  object  actually  stands. 

55465°— 19 17 


250  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

BEARING   TREES,    BEARING    OBJECTS,    AND    MEMORIALS. 

319.  Bearing  trees,  or  other  natural  objects,  are  to  be  selected 
for  marking  when  the  same  are  available  within  a  distance  of  5 
chains  of  the  corner  monument,  and  where  the  regular  quota,  here- 
inafter described,  is  not  available,  one  tree  or  object  will  be  marked 
in  each  section  affording  such  accessory.     A  full  description  of  the 
tree  or  object  will  be  embodied  in  the  field  notes  as  a  part  of  the 
record  of  the  corner  monument.     One  tree,  or  object,  will  be  marked 
in  each  section  cornering  at  the  monument,  when  available,  and  the 
true  course  and  horizontal  distance  from  the  exact  corner  point  to 
the  center  vertical  axis  of  the  tree  at  its  root  crown,  or  to  the  cross 
(X)  upon  a  marked    object,    will  be   carefully    determined  and 
recorded  with  the  description  of  the  tree,  or  object,  and  its  marks. 
The  species  of  a  tree  and  its  diameter,  at  breast  height,  will  be 
recorded;  and,  in  the  case  of  a  cliff  or  bowlder,  the  description  will 
embrace  such  essential  details  as  may  be  necessary  to  serve  for  its 
ready  identification. 

320.  The  marks  upon  a  bearing  tree  will  be  made  upon  the  side 
facing  the  corner  and  will  be  scribed  in  the  manner  already  outlined 
for  marking  tree  corner  monuments.     The  marks  will  embrace  the 
information  suggested  in  the  schedule  hereinafter  given,  with  such 
letters  and  figures  as  may  be  appropriate  for  a  particular  comer,  and 
will  include  the  letters  "  B  T  " ;  a  tree  will  always  be  marked  to  agree 
with  the  section  in  which  it  stands,  and  will  be  marked  in  a  vertical 
line  reading  downward,  ending  in  the  letters  "B  T"  at  the  lower 
end  of  the  blaze  approximately  6  inches  above  the  root  crown. 

321.  There  is  a  great  difference  in  the  longevity  of  trees,  and  in 
their  rate  of  decay,  etc. ;  trees  should  therefore  be  selected,  if  possible, 
with  a  view  to  the  length  of  their  probable  life,  their  soundness, 
favorable  site  conditions  and  size.    Sound  trees  from  6  to  8  inches 
in  diameter,  of  the  most  hardy  species,  favorably  located,  are  to  be 
preferred  for  marking.    Trees  less  than  4  inches  in  diameter  will 
not  be  selected  for  marking  if  larger  trees  are  available,  and  it  is 
generally  better  to  avoid  marking  fully  matured  trees,  especially 
those  showing  signs  of  decay.    Trees  less  than  4  inches  in  diameter, 
if  no  better  trees  are  available,  will  be  marked  with  the  letters 
"B  T"  only.    The  species,  size  and  exact  position  of  the  bearing 
trees  are  of  vital  importance,  as  this  data  will  generally  serve  to 
identify  a  bearing  tree  without  uncovering  the  marks,  or  even  to 
identify  two  or  more  stumps  after  all  evidence  of  the  marks  has 
disappeared. 


CORNER   MONUMENTS.  251 

322.  Generally  only  one  tree  will  be  marked  in  each  section  at 
a  particular  corner,  but  in  certain  instances,  hereinafter  described, 
two  trees  are  required  in  a  section.     In  such  cases  it  is  better  to 
select  trees  of  different  species,  or  of  widely  different  size,  direction 
or  distance,  if  the  trees  are  of  the  same  species,  in  order  that  confusion 
may  be  avoided  in  the  future  identification  of  a  remaining  tree  where 
the  companion  tree  has  disappeared. 

323.  A  cross  (X)  and  the  letters  "B  0"  and  the  section  number 
will  be  chiseled  into  a  bearing  object,  if  it  is  of  rock  formation, 
and  the  record  should  be  such  as  to  enable  another  surveyor  to 
determine  where  the  marks  will  be  found. 

324.  A  connection  to  any  permanent  artificial  object  or  improve- 
ment may  be  included  in  this  general  class  of  corner  accessories. 
The  field  notes  should  be  explicit  in  describing  such  objects,  and 
should  indicate  the  exact  point  to  which  a  connection  is  made,  as 
"southwest  corner  of  foundation  of  Smith's  house,"   "center  of 
Smith's  well,"  "pipe  of  Smith's  windmill,"  etc.    No  marks  will  be 
made  upon  private  property. 

325.  In  every  case  where  it  is  impossible  to  make  a  single  connec- 
tion to  a  bearing  tree  or  other  bearing  object,  as  above  described, 
and  where  a  mound  of  stone  or  pits  are  impracticable,  a  suitable 
memorial  will  be  deposited  at  the  base  of  the  monument.    A  memo- 
rial may  consist  of  any  durable  article  which  will  serve  to  identify 
the  location  of  the  corner  in  case  the  monument  is  destroyed.    Such 
articles  as  glassware,  stoneware,  a  marked  (X)  stone,  a  charred 
stake,  a  quart  of  charcoal,  or  pieces  of  metal  will  constitute  a  suit- 
able memorial.    A  full  description  of  such  articles  will  be  embodied 
in  the  field  notes  wherever  they  are  employed  as  a  corner  accessory. 

MOUND   OF   STONE. 

326.  Where  native  stone  is  available  and  the*  surface  of  the 
ground  is  favorable,  a  mound  of  stone  will  be  employed  as  an  ac- 
cessory to  a  corner  monument,  provided  that  a  full  quota  of  trees  or 
other  bearing  objects  can  not  be  utilized.    A  mound  of  stone  erected 
as  a  corner  accessory  will  be  built  as  stably  as  possible,  will  consist 
of  not  fewer  than   five  stones,  and  will  be  not  less  than  2  feet 
base  and  1J  feet  high.    In  stony  ground  the  size  of  the  mound  will 
be  sufficiently  increased  to  make  it  conspicuous.    The  position  of 
the  mound  will  be  as  shown  in  the  schedule  hereinafter  stated,  and 
the  nearest  point  on  its  base  will  be  separated  about  6  inches  distant 
from  the  monument.    The  field  notes  will  show  the  size  and  posi- 
tion of  the  mound. 


.252  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

327'.  Where  it  is  necessary  to  support  a  monument  in  a  stone 
mound,  no  additional  mound  will  be  employed  as  an  accessory;  and, 
if  bearing  trees  or  other  objects  are  not  available,  a  marked  (X) 
stone  or  other  memorial  will  be  deposited  at  the  base  of  the  monu- 

.ment. 

PITS. 

"828.  Where  the  full  quota  of  trees  or  other  bearing  objects  are 
unavailable  for  marking,  the  position  of  the  monument  will,  under 
certain  favorable  conditions,  be  evidenced  by  pits.  No  pits  should 
be  dug  in  a  roadway,  or  where  the  ground  is  overflowed  for  any  con- 
siderable period,  or  upon  steep  slopes,  or  where  the  earth  will  wash, 
'or  in  a  loose  or  light  soil,  or  where  there  is  no  native  sod,  or  where 
suitable  stone  for  a  mound  is  at  hand. 

A  firm  soil  covered  with  a  healthy  native  sod  is  most  favorable 
for  a  permanent  pit.  Under  such  conditions  the  pits  will  gradually 
fill  with  a  material  slightly  different  from  the  original  soil,  and  a  new 
species  of  vegetation  will  generally  take  the  place  of  the  native 
grass;  these  characteristics,  under  favorable  conditions,  make  it 
possible  to  identify  the  original  location  of  the  pits  after  the  lapse 
of  many  years. 

329.  All  pits  will  be  dug  18  inches  square  and  12  inches  deep, 
with  the  nearest  side  3  feet  distant  from  the  corner  monument, 
oriented  with  a  square  side  (and  not  a  corner)  towards  the  monu- 
ment, arranged   as  shown  in  the  schedule  hereinafter  given;  the 
earth  removed  will  be  scattered  in  such  a  way  that  it  will  not  again 
fill  the  pits.    A  description  of  the  pits  will  be  embodied  in  the 
field  notes,  and  will  include,  in  every  instance,  a  statement  of  their 
size  and  position;  this  is  particularly  important  in  view  of  the 
fact  that  the  practice  herein  outlined  differs  materially  (in  the  inter- 
est of  simplicity)  from  that  set  forth  in  earlier  editions  of  the  Manual. 

ARRANGEMENT  AND  MARKING  OF  CORNER  ACCESSORIES. 

330.  Standard  township  corners. 
Standard  section  corners. 

Two  bearing  trees,  one  in  each  section  north  of  the  standard 
parallel,  each  marked  "  S  C  "  and  the  township,  range  and  section;  as 

T  25  N  R  18  E  S  31  S  C  B  T. 
Mound  of  stone,  north  of  corner. 
Three  pits,  one  each  on  line  north,  east  and  west. 


CORNER    MONUMENTS.  253 

331.  Closing  township  corners. 
Closing  section  corners. 

Two  bearing  trees,  one  in  each  section  to  the  right  and  left  of  the 
closing  line,  each  marked  "C  C"  and  the  township,  range  and 
section;  as 

T24NR18ES6CCBT. 

Mound  of  stone,  on  the  closing  line. 

Three  pits,  one  on  the  closing  line  and  one  each  to  the  right  and 
left  on  the  line  closed  upon. 

332.  Corners  common  to  four  tovmships. 

Four  bearing  trees,  one  in  each  section,  each  marked  with  the 
township,  range  and  section;  as 

T22NR17ES1BT. 
Mound  of  stone,  south  of  corner. 
Four  pits,  one  each  on  line  north,  east,  south  and  west. 

333.  Corners  common  to  two  townships  only. 

Two  bearing  trees,  one  in  each  section  cornering  at  the  monument, 
each  marked  with  the  township,  range  and  section;  as 
T2NR7WS1BT. 

Mound  of  stone,  on  the  line  between  the  two  townships  cornering 
at  the  monument. 

Three  pits,  one  each  on  the  three  lines  connecting  at  the 
monument. 

334.  Corners  referring  to  one  township  only. 

Two  bearing  trees,  both  in  the  township  cornering  at  th  e  monument, 
each  marked  with  the  township,  range  and  section;  as 
T  23  N  R  19  W  S  36  B  T. 

Mound  of  stone,  in  the  township  cornering  at  the  monument,  at 
45°  from  cardinal  direction  at  the  monument. 

Two  pits,  one  each  on  the  two  lines  connecting  at  the  monument. 

335.  Corners  common  to  four  sections. 

Four  bearing  trees,  one  in  each  section,  each  marked  vrith  the 
township,  range  and  section;  as 

T  26  N  R  17  E  S  35  B  T. 

Mound  of  stone,  west  of  corner. 

Four  pits,  one  in  each  section  northeast,  southeast,  southwest  and 
northwest. 

336.  Section  corners  common  to  two  sections  only. 

Two  bearing  trees,  orue  in  each  section  cornering  at  the  monument, 
each  marked  with  the  township,  range  and  section;  as 
T  14  S  R  17  E  S  12  B  T. 


254  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

Mound  of  stone,  on  the  line  between  the  two  sections  cornering  at 
the  monument. 

Two  pits,  one  in  each  section  at  45°  from  cardinal  direction  at  the 
monument. 

337.  Section  corners  referring  to  one  section  only. 

Two  bearing  trees,  both  in  the  section  cornering  at  the  monument, 
each  marked  with  the  township,  range  and  section;  as 
T  27  N  R  16  W  S  17  B  T. 

Mound  of  stone,  in  the  section  cornering  at  the  monument,  at  45° 
from  cardinal  direction  at  the  monument. 

Two  pits,  one  3  feet  and  one  6  feet  distant,  both  in  the  section  cor- 
nering at  the  monument,  at  45°  from  cardinal  direction  at  the  monu- 
ment. 

338.  Standard  quarter-section  corners. 

Two  bearing  trees,  both  north  of  the  standard  parallel,  each  marked 
"  J"  and  "S  C"  and  the  section;  as 

i  S  36  S  C  B  T. 

Mound  of  stone,  north  of  corner. 
Two  pits,  one  each  on  line  east  and  west. 

339.  Quarter-section  corners  of  maximum  control. 

Two  bearing  trees,  one  in  each  section,  each  marked  "J"  and  the 
section;  as 

i  S  16  B  T. 

Mound  of  stone:  (a)  On  a  meridional  line,  west  of  corner;  and, 
(b)  on  a  latitudinal  line,  north  of  corner. 

Two  pits,  one  in  each  direction  on  the  line  passing  through  the 
monument. 

340.  Quarter-section  corners  of  minimum  control. 

Two  bearing  trees,  both  in  the  particular  section  which  is  con- 
cerned, each  marked  "  J"  and  the  section;  as 
JS7BT. 

Mound  of  stone,  in  the  particular  section  which  is  concerned,  in  a 
cardinal  direction  from  the  monument. 

Two  pits,  one  in  each  direction  on  the  line  passing  through  the 
monument. 

341.  Meander  corners. 

Two  bearing  trees:  (a)  On  a  standard  parallel  or  other  line  con- 
trolling surveys  to  one  side  only,  both  in  the  particular  section 
which  is  concerned;  and  (b)  on  all  other  lines,  one  in  each  section 


CORNER   MONUMENTS. 


255 


to  the  right  and  left  of  the  line;  all  marked  "M  0"  and  with  the 
township,  range  and  section;  as 

T  25  N  R  14  E  S  32  M  C  B  T. 

Mound  of  stone,  on  the  surveyed  line  on  the  opposite  side  of  the 
monument  from  the  meanderable  body  of  water. 

Two  pits,  one  3  feet  and  one  6  feet  distant,  on  the  surveyed  line 
on  the  opposite  side  of  the  monument  from  the  meanderable  body 
of  water. 

342.  The  interior  quarter-section  and  all  sixteenth-section  corners, 
when  required  by  the  written  special  instructions. 

Two  bearing  trees,  marked  (with  letters  and  figures  ending  in 
"B  T")  as  shown  in  the  following  diagram: 

Mound  of  stone,  in  a  cardinal  direction  from  the  monument,  as 
shown  (with  symbol  "  ^>  ")  in  the  following  diagram: 

Two  pits,  in  a  cardinal  direction  from  the  monument,  aa  shown 
(with  symbol  "  D  ")  in  the  following  diagram: 


p  -                      —  u  U  — 

W&S368T 

E^S36BT 

~  1 

n                       a 
NIB  i  N£            Nw4  Nw,4 
>cs.  j                   jfi*. 

CN|g    CNjg 

,D       , 

5  35  1  S  36                  S  36    S  36 

S36    S36 

S36    S36 

~~^3% 

BT  D  BT                         BT  D  BT 

BT  D  BT 

BT  D  BT 

BT  C 

I       x 

1 

1 

1 

1 

t 

CWfsS36BT 

04;       ci 

CE4S36BT 

^3, 

1-1     -^flS>-      r-i 

--336^g^.    S36- 

CV/4S36BT 

BT         BT 

a 

1 

1 

1 

1 

1 

1 

i 

I 

S35 

S«6                          SW.6     SW(^ 

CS(i    CSft                    SEft 

SEfe                        S.-g    S,i 

S36                      S36    S36 

S~36      S3S                     S36 

S36 

-«£XE> 

S36    S3I 

8T  p  BT                       BT  p  BT 

BT   D   BT                        BT  D  BT 

BTDBT 

1 

. 

1 

r 

l" 

j                                      1 

i 

,W,^S36BT                               ;                              E^SSSOT 

1 

*J3&-    r- 

.      L  .  .    _                                    r,    -& 

.  J 

256 


MANUAL  OF  SURVEYING  INSTRUCTIONS. 


34:8.  Sixteenth-section  corners  of  minimum  control. 

Two  bearing  trees,  both  in  the  particular  section  which  is  con- 
cerned, each  marked  with  a  key  letter  (N,  E,  S  or  W)  to  indicate 
the  position  of  the  monument,  and  "A"  and  the  section;  as 


r 

V  

.  £ 

n 

K 

c 

L 

V 

I 

J 

N  &SI8BT. 


Key 

Mound  of  stone,  in  the  particular  section  which  is  concerned,  In 
a  cardinal  direction  from  the  monument. 

Two  pits,  one  in  each  direction  on  the  section  line  passing  through 
the  monument. 

344.  Special  and  auxiliary  meander  corners. 

Two  bearing  trees,  each  marked  "SMC"or"AMC,"as  the  case 
may  be,  and  the  section;  as 

S  14  S  M  C  B  T,  or 
S  14  A  M  C  B  T. 

Mound  of  stone,  on  the  opposite  side  of  the  monument  from  the 
meanderable  body  of  water. 

Two  pits,  one  3  feet  and  one  6  feet  distant,  on  the  opposite  side  of 
the  monument  from  the  meanderable  body  of  water. 

345.  Closing  subdivision-of-section  corners. 

Two  bearing  trees,  both  in  the  particular  section  which  is  con- 
cerned, each  marked  "C  C"  and  the  section;  as 
S9CCBT. 

Mound  of  stone,  on  the  closing  line. 

Three  pits,  one  on  the  closing  line  and  one  each  to  the  right  and 
left  on  the  line  closed  upon. 

346.  Miscellaneous  angle  points  along  irregular  boundaries. 

(a)  Two  bearing  trees,  where  the  monuments  are  less  than  1  mile 
apart,  one  on  each  side  of  the  boundary;  and  (b)  four  bearing  trees, 
where  the  monuments  are  1  mile  or  more  apart,  two  on  each  side  of 
the  boundary;  each  marked  "A  P"  and  a  serial  or  section  number, 


CORNER   MONUMENTS.  257 

or  both,  also  the  initials  or  abbreviation  of  the  State,  reservation, 
giant,  private  claim  or  public  land,  as  appropriate;  as 
A  P  2  TR  37  B  T,  and 

A  P  S  14  B  T  (for  "  angle  point  No.  2"  on  the  boundary 

of  a  private  claim  "Tract  No.  37  "  fall- 
ing on  surveyed  land). 

Mound  of  stone,  on  the  medial  line  between  the  boundary  lines 
intersecting  at  the  monument,  and  in  the  direction  toward  the  S'ate, 
reservation,  grant  or  private  claim. 

Two  pits,  one  in  each  direction  on  the  lines  intersecting  at  the 
monument. 

347.  Intermediate  corners  along  irregular  "boundaries, 
(a)  Two  bearing  trees,  where  the  monuments  are  less  than  1  mile 
apart,  one  on  each  side  of  the  boundary;  and  (b)  four  bearing  trees, 
where  the  monuments  are  1  mile  or  more  apart,  two  on  each  side  of 
the  boundary;  each  marked  with  the  number  of  the  mile  or  half- 
mile  corner  and  the  letter  "M"  (to  indicate  "mile  corner"),  and 
the  initials  or  abbreviation  of  the  State,  reservation,  grant,  private 
claim  or  public  land,  as  appropriate;  as 
47  M  COLO  BT,  and 

47  M  OKLA  BT  (for  "47th  mile"  corner  on  the  boundary 
line  between  the  States  of  "Colorado" 
and  "Oklahoma"). 

Mound  of  stone,  on  a  line  at  right  angles  to  the  boundary,  and  in 
direction  toward  the  State,  reservation,  grant  or  private  claim. 
Two  pits,  one  in  each  direction  on  the  boundary. 


CHAPTER  V. 

RESTORATION  OF  LOST   CORNERS. 

IDENTIFICATION  OF  EXISTENT  CORNERS. 

348.  It  is  the  purpose  of  this  chapter  of  the  Manual  to  outline 
the  guiding  principles  which  are  to  be  observed  in  the  identification 
of  existent  corners,  and  thereafter  to  set  forth  the  particular  rules 
which  are  to  be  applied  in  the  recovery  of  the  position  of  lost  corners 
originally  established  in  the  execution  of  the  United  States  rec- 
tangular surveys. 

All  surveyors,  whether  employed  by  the  United  States  or  not, 
are  cautioned  to  note  the  difference  between  the  regulations  per- 
taining to  the  establishment  of  the  original  surveys  of  the  public 
lands  and  those  relating  to  the  subsequent  identification  of  said 
official  surveys  and  the  replacement  of  missing  monuments  thereof. 

In  the  extension  of  the  rectangular  surveys  it  devolves  upon  the 
United  'States  surveyor  to  identify  the  initial  lines  of  his  group  and 
to  replace  all  lost  corners  thereof.  On  the  other  hand  in  the  sub- 
division of  sections  and  in  the  location  of  property  lines  generally, 
it  falls  to  the  county  or  other  local  surveyor  to  identify  the  official 
corners,  and  where  a  required  corner  is  missing  the  local  surveyor 
will  be  called  upon  to  recover  the  point.  Thus  it  will  be  seen  that 
local  as  well  as  United  States  surveyors  are  constantly  called  upon 
to  search  for  existing  evidence  of  original  monuments,  and  in  this 
work  the  surveyors  will  be  guided  by  the  same  general  methods. 
Should  the  search  for  a  monument  result  in  failure,  the  appropriate 
restorative  surveying  process  to  be  observed  by  either  surveyor  will 
be  based  upon  the  same  rules  as  hereinafter  outlined.  The  text 
that  follows  draws  no  distinction  between  the  duties  of  the  two 
classes  of  surveyors. 

349.  The  terms  " corner"  and  " monument"  are  used  largely  in 
the  same  sense,  though  a  distinction  should  be  noted  to  clarify  the 
subject  matter  of  this  chapter.    The  term  " corner"  is  employed 
to  denote  a  point  determined  by  the  surveying  process,  whereas  the 
"monument"  is  the  physical  structure  erected  for  the  purpose  of 
marking  the  corner  point  upon  the  earth's  surface. 

259 


260  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

350.  An  existent  corner  is  one  whose  position  can  be  identified 
by  comparing  the  evidence  of  the  monument  or  its  accessories  on 
the  ground,  with  the  record  contained  in  the  field  notes  of  the 
original  survey,  or  where  the  point  can  be  determined  otherwise 
by  suitable  testimony. 

851.  The  process  of  again  bringing  to  light  the  physical  evidence 
of  an  original  monument  is  founded  on  the  principle  of  intelligent 
search  for  the  calls  of  the  field  notes  of  the  original  survey,  guided 
by  the  controlling  influence  of  known  points.  The  problems 
incident  to  the  search  are  vastly  simplified  whenever  a  retracement 
may  be  projected  from  known  points,  and  the  final  search  for  a 
monument  should  cover  the  zone  surrounding  one,  two,  three  or 
four  temporary  points  as  may  be  determined  by  connections  with 
known  corners  in  one,  two,  three  or  four  directions,  according  to 
the  number  of  points  which  will  ultimately  control  the  relocation 
in  case  the  corner  in  question  should  be  declared  lost. 

352.  The  character  of  the  original  monument  is  the  most  impor- 
tant factor  in  regard  to  its  lasting  qualities,  and  the  search  should 
be  directed  to  an  examination  for  such  evidence  as  may  reasonably 
be  expected  to  remain.     The  evidence  is  bound   to  range  from 
that  which  is  least  conclusive  to  that  which  is  unquestionable,  and 
the  requisite  support  of  corroborative  evidence  is  necessary  in 
direct  proportion  to  the  uncertainty  of  any  feature  regarding  whose 
authenticity  there  may  be  danger  of  dispute. 

A  stone,  wooden  post,  tree  corner,  deposit  corner,  and  the  modern 
iron  post  monument  are  all  subject  to  more  or  less  deteriorating 
changes  through  various  influences,  depending  upon  the  character 
of  the  original  monument,  its  local  site  conditions,  and  the  lapse  of 
time,  and  all  such  factors  should  be  taken  into  consideration  when 
comparing  the  particular  evidence  in  question  with  the  description 
contained  in  the  original  field  notes. 

353.  If  the  evidence  of  the  monument  is  not  fully  conclusive,  the 
surveyor's  attention  will  be  directed  at  once  to  the  record  acces- 
sories; this  step  is  so  generally  necessary  that  it  should  be  considered 
simultaneously  with  the  search  for  the  monument;  in  fact,  in  their 
broader  significance  the  accessories  are  a  part  of  the  monument. 

The  underlying  principles  relating  to  the  identification  of  the 
corner  accessories,  subject  to  the  changes  which  may  be  expected  in 
the  period  intervening  after  the  date  of  the  original  survey,  have 
already  been  fully  outlined  in  Chapter  IV.  It  will  suffice  to  state 


RESTORATION  OF  LOST  CORNERS.          261 

that  the  evidence  of  the  accessories  should  agree  with  the  record 
contained  in  the  field  notes  of  the  original  survey,  subject  only  to 
such  changes  as  may  reasonably  be  expected. 

354.  In  case  of  material  disagreement  between  the  particular 
evidence  in  question  and  the  record  calls,  the  process  of  elimina- 
tion of  those  features  regarding  which  there  may  be  doubt,  after 
making  due  allowance  for  natural  changes,  will  serve  a  most  useful 
purpose,  as  follows: 

(a)  The  character  and  dimensions  of  the  monument  in  evidence 
should  not  be  widely  different  from  the  record ; 

(b)  The  markings  in  evidence  should  not  be  inconsistent  with 
the  record;  and, 

(c)  The  nature  of  the  accessories  in  evidence,  including  size, 
position  and  markings,  should  not  be  greatly  at  variance  with  the 
record. 

A  certain  measure  of  allowance  for  ordinary  discrepancies  should 
enter  into  the  consideration  of  the  evidence  of  a  monument  and  its 
accessories,  and  no  definite  rule  can  be  laid  down  as  to  wrhat  shall  be 
sufficient  evidence  in  such  cases.  Much  must  be  left  to  the  skill, 
fidelity  and  good  judgment  of  the  surveyor  in  the  performance  of 
his  work,  ever  bearing  in  mind  the  relation  of  one  monument  to 
another,  and  the  relation  of  all  to  the  recorded  natural  objects  and 
items  of  topography. 

355.  A  corner  will  not  be  considered  as  lost  if  its  position  can  be 
recovered  satisfactorily  by  means  of  the  testimony  and  acts  of  wit- 
nesses having  positive  knowledge  of  the  precise  location  of  the 
original  monument.    The  expert  testimony  of  surveyors  who  may 
have  identified  the  original  monument  prior  to  its  destruction  and 
thereupon  recorded  new  accessories  or  connections,  etc.,  is  by  far 
the^most  reliable,   though  landowners  are  often  arjle  to  furnish 
valuable  testimony.    The  greatest  care  is  necessary  in  order  to 
establish  the  bona  fide  character  of  the  record  intervening  after  the 
destine tion  of  an  original  monument.     Full  inquiry  may  often 
serve  to  bring  to  light  various  records  relating  to  the  original  corners, 
and  memoranda  of  private  markings,  etc.,  and  the  surveyor  should 
make  use  of  all  such  sources  of  information .    The  matter  of  boundary 
disputes  should  be  carefully  looked  into  in  so  far  as  adverse  claimants 
may  base  their  contentions  upon  evidence  of  the  original  survey, 
and  if  such  disputes  have  resulted  in  a  boundary  suit,  the  record 
testimony  and  the  court's  decision  should  be  carefully  examined 


262  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

relative  to  any  information  which  may  shed  light  upon  the  position, 
of  an  original  monument. 

The  testimony  of  individuals  may  relate  to  knowledge  of  the  orig- 
inal monument  or  the  accessories,  prior  to  their  destruction,  or  to 
any  other  marks  fixing  the  locus  of  the  original  survey,  and  the  value 
of  such  testimony  may  be  weighted  in  proportion  to  its  completeness 
and  agreement  with  the  calls  of  the  field  notes  of  the  original  survey, 
also  upon  the  steps  taken  to  preserve  the  location  of  the  original 
marks.  All  such  evidence  should  be  put  to  the  severest  possible 
tests  by  confirmation  relating  to  known  original  corners  and  other 
calls  of  the  original  field  notes,  particularly  to  line  trees,  blazed 
lines  and  items  of  topography. 

It  is  impossible  to  outline  a  definite  rule  for  the  acceptance  or 
non-acceptance  of  the  testimony  of  individuals.  Corroborative  evi- 
dence becomes  necessary  in  direct  proportion  to  the  uncertainty  of 
the  particular  statements  advanced  by  the  individual  who  testifies. 
It  will  be  well  for  the  surveyor  to  bear  in  mind  that  conflicting 
statements  and  contrary  views  of  interested  parties  are  fruitful  of 
boundary  disputes. 

356.  In  those  cases  where  witness  corners  were  established  in  the 
original  survey,  the  true  point  for  the  corner  will  be  controlled  by 
such  witness  corner,  when  the  latter  can  be  identified,  by  reference 
to  the  record  in  accordance  with  the  general  plan  of  the  survey. 
The  usual  diligent  search  will  be  made  for  witness  corners,  but  where 
the  same  can  not  be  identified  the  position  of  the  true  point  for  the 
corner  will  usually  be  of  major  importance,  rather  than  the  point 
for  the  witness  corner,  and  in  such  instances  the  surveyor  will  pro- 
ceed directly  to  the  re-determination  of  the  true  corner  position, 
adopting  the  particular  methods  which  should  govern  the  case  in 
hand.     Should  it  become  necessary  to  restore  a  lost  witness  corner 
the  general  principles  hereinafter  outlined  will  be  observed. 

357.  In  the  absence  of  an  original  monument,  a  line  tree,  or  a  defi- 
nite connection  to  natural  objects,  or  to  improvements,  which  can 
be  identified,   may  each  fix  a  point  of  the  original  survey  for 
both  latitude  and  departure.    The  mean  position  of  a  blazed  line, 
when  identified  as  the  original  line,  may  sometimes  help  to  fix  a 
meridional  line  for  departure,  or  a  latitudinal  line  for  latitude.    Other 

alls  of  the  original  field  notes  in  relation  to  vaiious  items  of  topogra- 
phy may  assist  materially  in  the  recovery  of  the  locus  of  the  original 
survey.  Such  evidence  may  be  developed  in  an  infinite  variety. 


RESTORATION  OF  LOST  CORNERS.          263 

It  may  be  only  such  as  to  disprove  other  questionable  t features, 
or  it  may  guide  the  surveyor  in  a  general  way  in  arriving  at  the 
immediate  vicinity  of  a  line  or  corner,  or  in  its  best  phases  may  be 
such  as  to  fix  the  position  of  a  line  or  corner  beyond  any  doubt. 

358.  A  certain  measure  of  allowance  should  be  made  for  ordinary 
discrepancies  in  the  calls  relating  to  items  of  topography.    Such 
evidences  should  be  considered  more  particularly  in  the  aggregate, 
and  when  they  are  found  to  be  corroborative  an  average  may  be 
secured  to  control  the  final  adjustment,  which  will  be  governed 
largely  by  the  evidences  nearest  the  particular  corner  in  question, 
giving  the  greatest  weight  to  those  features  which  agree  most  har- 
moniously with  the  record,  and  to  such  items  as  afford  definite  con- 
nection.   A  careful  analysis  will  generally  reveal  the  merits  of  au- 
thentic evidences  as  opposed  to  unreliable  features  bearing  re- 
semblance to  the  calls  of  the  field  notes,  and  in  this  matter  the  sur- 
veyor will  find  an  opportunity  to  exercise  his  skill  to  the  fullest 
capacity. 

359.  It  is  a  matter  of  utmost  importance  to  determine  where  an 
identified  call  of  the  original  field  notes  shall  operate  to  control  for 
both  latitude  and  departure,  or  for  either  coordinate  by  itself,  and 
finally  as  to  the  necessity  for  applying  the  rules  for  proportionate 
measurement  where  the  distance  between  the  identified  points  is 
considerable. 

RESTORATION  OF  LOST  CORNERS. 

360.  A  lost  corner  is  a  point  of  a  survey  whose  position  can  not 
be  determined,  beyond  reasonable  doubt,  either  from  original  traces 
or  from  other  reliable  evidence  relating  to  the  position  of  the  original 
monument,  and  whose  restoration  on  the  earth's  surface  can  be 
accomplished  only  by  means  of  a  suitable  surveying  process  with 
reference  to  inter-dependent  existent  corners. 

361.  The  surveyor  is  not  prepared  to  consider  the  restoration  of 
a  lost  corner  until  he  has  exhausted  every  other  means  of  identifying 
its  original  position,  and  at  this  stage  of  his  work  he  should  have 
determined  upon  an  approximate  position  of  the  original  monument 
based  upon  his  findings  resulting  from  retracements  leading  from 
known  corners  to  the  lost  corner,  from  one,  two,  three  or  four  direc- 
tions in  accordance  with  the  plan  of  the  original  survey.    The  prin- 
ciple of  proportionate  measurement,  which  most  nearly  harmonizes 
surveying  practice  with  the  legal  and  equitable  considerations 
involved  in  controversies  concerning  lost  land  boundaries,  enters 


264  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

into  the  problem  at  this  stage,  and  this  plan  of  relocating  a  lost 
corner  will  always  be  employed  unless  outweighed  to  the  contrary 
by  physical  evidence  of  the  original  survey.  In  cases  where  the 
relocated  corner  can  not  be  made  to  harmonize  with  all  the  calls 
of  the  original  field  notes,  due  to  unexplained  discrepancy  which 
is  made  apparent  by  the  retracement,  the  surveyor  is  required  to 
determine  which  calls  will  be  given  major  control,  and  those  which 
must  be  subordinated. 

362.  The  preliminary  retracements    furnish  the  only  possible 
means  of  arriving  at  the  discrepancies  of  the  courses  and  distances 
of  the  original  survey  as  compared  with  those  derived  in  the  process 
of  re-running  the  lines,  and  the  whole  problem  of  proportionate  meas- 
urement is  one  involving  the  adjustment  of  said  discrepancies.    The 
restoration  of  the  lost  corners  can  not  proceed  until  the  retracement 
of  the  original  survey  has  been  completed.    The  retracement  will 
be  based  upon  the  courses  and  distances  returned  in  the  field  notes 
of  the  original  survey,  or  the  equivalent  by  calculation,  initiated 
and  closed  upon  known  original  corners.    Temporary  stakes  for 
future  use  in  the  relocation  of  all  lost  corners  may  be  set  when 
making  the  retracements. 

363.  As  has  been  observed,  existing  original  corners  can  not  be 
disturbed;  consequently  discrepancies  between  the  new  and  the 
original  record  measurements  of  the  line  connecting  the  identified 
original  corners  will  not  in  any  manner  affect  measurements  beyond 
said  corners,  but  the  differences  will  be  distributed  proportionally 
within  the  several  intervals  embraced  in  the  line  in  question. 

—  364.  A  proportionate  measurement  is  one  resulting  in  concordant 
Telation  between  all  parts  of  an  original  record  length  of  a  line  and 
the  new  distances  given  to  the  several  parts  as  determined  by  the 
re-measurement,  in  such  a  manner  that  the  new  distance  given  to 
any  part  of  a  line  shall  bear  the  same  relation  to  the  original  record 
length  of  that  part  of  the  line  as  the  new  measurement  of  the  whole 
line  bears  to  the  original  record  length  of  said  line.  The  ordinary 
field  problem  consists  in  distributing  the  excess  or  deficiency 
determined  by  comparing  the  new  measurement  with  the  record 
distance  between  two  original  existent  monuments,  in  such  a  man- 
ner that  the  amount  of  excess  or  deficiency  given  to  each  interval 
shall  bear  the  same  proportion  to  the  whole  difference  as  the  record 
length  of  the  interval  bears  to  the  whole  record  distance.  After 
having  applied  the  proportionate  difference  to  the  record  length  of 


RESTORATION   OF  LOST  CORNERS.  265 

each  interval  the  sum  of  the  adjusted  lengths  will  equal  the  new 
measurement  of  the  whole  distance. 

365.  The  term  "single  proportionate  measurement"  is  applied 
to  a  new  measurement  made  on  a  single  line  to  determine  the  posi- 
tion thereon  for  restoring  a  lost  corner,  for  example,  a  quarter-section 
corner  on  line  between  two  original  section  corners.    The  term 
"double  proportionate  measurement"  is  employed  to  signify  new 
measurements  made  between  four  original  corners  on  intersecting 
meridional  and  latitudinal  lines  for  the  purpose  of  fixing  by  relation 
to  both  lines  the  position  of  a  lost  corner,  for  example,  a  corner 
common  to  four  sections  or  four  townships. 

366.  It  will  almost  invariably  happen  that  discrepancies  will  be 
developed  between  the  new  measurements  and  the  original  measure- 
ments recorded  in  the  field  notes.    When  these  differences  occur  the 
surveyor   will   generally   be   required   to   adopt   a   proportionate 
measurement  based  upon  a  process   conforming  to  the   method 
followed  in  the  original  survey.    The  principle  of  the  preponder- 
ance of  one  line  over  another  of  less  importance  is  recognized,  in 
order  to  determine  upon  the  procedure  relative  to  single  or  double 
proportionate  measurement,  or  other  rule  to  be  adopted  in  order 
to  limit  the  control  and  at  the  same  time  harmonize  the  restorative 
process  with  the  method  followed  in  the  original  survey.    Thus 
standard  parallels  will  be  given  precedence  over  other  township 
exteriors,  and  the  latter  will  be  given  precedence  over  subdivisional 
lines;  section  corners  will  be  relocated  before  the  position  of  lost 
quarter-section  corners  can  be  determined. 

PRIMARY   METHODS, 
(a)   DOUBLE  PROPORTIONATE   MEASUREMENT. 

367 .  The  method  of  double  proportionate  measurement  is  generally 
applicable  to  the  restoration  of  lost  corners  of  four  townships  and  of 
lost  interior  corners  of  four  sections.     It  is  the  best  example  of  the 
basic  principle  that  monuments  north  and  south  should  control  the 
latitudinal  position  of  a  lost  corner,  and  monuments  east  and  west 
should  control  the  longitudinal  position  of  a  lost  corner,  upon  a  plan 
by  which  the  influence  of  one  identified  original  corner  is  balanced 
by  the  control  of  a  corresponding  original  corner  upon  the  opposite 
side  of  a  particular  missing  corner  which  is  to  be  restored,  each 
identified  original  corner  being  given  a  controlling  weight  inversely 
proportional  to  its  distance  from  the  lost  corner. 

55465°— 19 18 


266  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

368.  In  order  to  restore  a  lost  corner  of  four  townships  where  all 
of  the  connecting  lines  have  been  established  in  the  field,  a  retrace- 
ment  will  first  be  made  between  the  nearest  identified  original 
corners  on  the  meridional  line,  north  and  south  of  the  missing  corner, 
upon  which  line  a  temporary  stake  will  be  placed  at  the  proper 
proportionate  distance.     This  will  determine  the  latitude  of  the 
lost  corner.     Next,  the  nearest  original  corners  on  the  latitudinal  line 
will  be  connected  and  a  point  thereon  will  be  determined  by  pro- 
portionate measurement  in  a  similar  manner,  independent  of  the 
temporary  stake  on  the  meridional  line.     The  second  temporary 
point  will  determine  the  position  of  the  lost  corner  in  departure. 
Then  through  the  first  temporary  stake  run  a  line  east  or  west,  and 
through  the  second  temporary  stake  a  line  north  or  south,  as  relative 
situations  may  determine.    The  intersection  of  the  two  lines  last  run 
will  define  the  position  of  the  restored  corner  by  "double  propor- 
tionate measurement." 

369.  In  the  accompanying  diagram  the  points  "A, "  "B,"  "C" 
and  "D"  (on  the  small  scale)  represent  four  original  corners;  and 
(on  the  large  scale)  "E"  represents  the  proportional  point  between 
"A"  and  "B,"  for  measurement  only,  and  similarly,  "F"  represents 
the  proportional  point  between  "C"  and  "D."     The  point  "X" 
satisfies  the  first  control  for  latitude,  and  the  second  control  for 
departure. 

370.  The  plan  of  double  proportionate  measurement  will  be 
applied  to  the  restoration  of  lost  corners  of  four  townships  where  all 
the  lines  therefrom  have  been  run.     Lost  interior  corners  of  four 
sections,  where  all  the  lines  therefrom  have  been  run,  will  also  be 
reestablished   by   double   proportionate   measurement,    after  first 
relocating  the  required  lost  section  corners  on  the  township  exteriors. 
When  a  number  of  corners  of  four  sections,  and  the  intermediate 
quarter-section  corners,  are  missing  on  all  sides  of  the  one  sought 
to  be  reestablished,  the  entire  distance  must,  of  course,  be  re- 
measured  between  the  nearest  identified  corners  both  north  and 
south,  and  east  and  west,  in  accordance  with  the  rule  laid  down. 

371.  Where  one  of  the  connecting  lines  has  not  been  established 
in  one  direction  from  the  missing  township  or  section  corner,  the 
record  distance  to  the   nearest  identified  corner  in  the  opposite 
direction  will  prevail  in  lieu  of  a  proportional  measurement.     Thus, 
in  the  same  diagram,  if  the  latitudinal  line  in  the  direction  of 
the  point  "D"  had  not  been  established  in  the  original  survey,  the' 


RESTORATION  OF  LOST  CORNERS. 
I 


267 


r- 

25 

.  -j.  — 
1 

30             1            29 
1 
1 

36 

"1                     ^ 
1 

3!              I            32 
| 

X 

1               # 

. 
1 

L- 

I 

€             1            5 

1 

L.          _J 

fig, 67. 


268  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

position  of  the  point  "F"  in  departure  would  have  been  deter- 
mined by  reference  to  the  record  distance  from  the  point  "C, " 
whereupon  the  point  "X  "  would  have  been  fixed  by  cardinal  offsets 
from  the  points  "E"  and  "F"  as  before.  Again,  in  rare  instances, 
where  the  intersecting  lines  have  been  originally  established  in 
only  two  of  the  directions,  the  record  distances  to  the  nearest  iden- 
tified corners  on  the  two  lines  will  control  the  position  of  the  tem- 
porary points  from  which  the  cardinal  offsets  are  to  be  made. 

(&)  SINGLE  PROPORTIONATE  MEASUREMENT. 

372.  The  method  of  single  proportionate  measurement  is  gener- 
ally applicable  to  the  restoration  of  lost  corners  on  standard  parallels 
and  other  lines  established  with  reference  to  definite  alinement  in 
one  direction  only.     Intermediate  corners  on  township  exteriors 
and  other  controlling  boundary  lines  are  to  be  included  in  this  class. 

373.  In  order  to   restore   a   lost  corner  by  single  proportionate 
measurement,  a  retracement  will  be  made  connecting  the  nearest 
identified  regular  corners  upon  the  particular  line  in  question,  the 
record  of  which  shows  no  deflection  in  alinement;  a  temporary  stake 
will  be  set  on  the  preliminary  line  at  the  original  record  distance; 
the  total  distance  will  be  measured,  also  the  falling  at  the  objective 
corner.     The  temporary  stake  will  then  be  adjusted  for  the  pro- 
portional part  of  the  difference  between  the  record  distance  and 
the  re-measurement,   also  for  its  proportional  part  of  the  falling. 
Thus  the  adjusted  position  will  fall  on  the  true  line  connecting  the 
nearest  identified  corners,  and  at  the  same  proportional  interval 
from  either  as  existed  in  the  original  survey.    Any  number  of  lost 
points,  on  the  same  straight  line,  may  be  recovered  by  the  same 
plan,  setting  a  temporary  corner  for  each  at  the  time  when  making 
the  retracement.     On  the  retracement  of  an  east  and  west  line,  the 
proper  adjustments  to  secure  the  true  latitudinal  curve  should  be 
allowed  for  as  outlined  in  Chapter  II. 

374.  Lost  standard  corners  will  be  restored    to  their  original 
positions  on  a*  base  line,  standard  parallel  or  correction  line,  by 
single  proportionate  measurement  on  the  line  connecting  the  nearest 
identified  original  standard  corners  on  opposite  sides  of  the  missing 
corner  or  corners,  as  the  case  may  be.     The  term  "original  standard 
corners "  will  be  understood  to  designate  standard  township,  section 
and    quarter-section    corners,    meander    corners    terminating    the 
survey  of  a  standard  parallel,  and  closing  corners  in  those  cases 
where  they  were  originally  established  during  the  survey  of  a 


RESTORATION  OF  LOST  CORNERS.  26D 

standard  parallel  as  corners  from  which  to  project  surveys  to  the 
south.  No  other  meander  or  closing  corners  along  a  standard  par- 
allel will  control  the  restoration  of  lost  standard  corners. 

375.  All  lost  exterior  section  and  quarter-section  corners  will  be 
restored  by  single  proportionate  measurement  between  the  nearest 
identified  corners  on  opposite  sides  of  the  missing  corner,  north  and 
south  on  a  meridional  line,  or  east  and  west  on  a  latitudinal  line, 
after  the  township  corners  have  been  identified  or  relocated.    An 
exception  to  this  rule  will  be  noted  in  the  case  of  any  exterior  the 
record  of  which  shows  irregularities  in  alinement  between  the  ter- 
minal township  corners.     (See  sec.  380.) 

376.  All  lost  interior  quarter-section  corners  will  be  restored  by 
single  proportionate  measurement  between  the  adjoining  section 
corners,  after  the  section  corners  have  been  identified  or  relocated. 

377.  Lost  meander  corners,  originally  established  on  a  line  pro- 
jected across  the  meanderable  body  of  water  and  marked  upon  the 
opposite  side  thereof   will  be  relocated   by  single  proportionate 
measurement,  after  the  section  or  quarter-section  corners  upon  the 
opposite  sides  of   the  missing  meander  corner   have   been   duly 
identified  or  relocated. 

(C)  CLOSING  CORNERS. 

378.  In  order  to  reestablish  a  lost  closing  corner  on  a  standard 
parallel  or  other  controlling  boundary,  the  line  closed  upon  will' be 
retraced,  beginning  at  the  corner  on  the  standard  parallel  or  other 
controlling  boundary  from  which  the  connecting  measurement  was 
originally  made,  itself  properly  identified  or  relocated;  a  temporary 
stake  will  be  set  at  the  original  record  connecting  distance,  and  the 
total  distance  and  falling  will  be  noted  at  the  next  regular  corner  on 
the  opposite  side  of  the  missing  closing  corner.    The  temporary  stake 
will  then  be  adjusted  as  in  single  proportionate  measurement,  i.  e., 
the  closing  corner  will  be  reestablished  on  the  true  line  closed  upon 
at  the  proper  proportional  interval  between  the  nearest  regular  cor- 
ners to  the  right  and  left.    An  identified  closing  corner  not  actually 
located  in  the  line  closed  upon  will  determine  the  direction  of  the 
closing  line,  but  not  its  legal  terminus;  the  latter  is  bound  to  fall  at 
the  true  point  of  intersection  of  the  two  lines.    The  position  of  a 
restored  closing  corner  should  be  verified  by  a  retracement  of  the 
line  whose  terminus  it  was  designed  to  mark.     (See  sec.  384.) 


270  MANUAL,  OF  SURVEYING  INSTRUCTIONS. 

SECONDARY  METHODS. 

379.  The  following  methods  involve  special  applications  of  the 
general  rules  of  proportionate  measurement  for  adoption  in  unusual 
cases  where  the  ordinary  control  can  not  be  obtained. 

(d)  BROKEN  BOUNDARIES. 

380.  In  order  to  restore  one  or  more  lost  corners  on  a  broken  or 
irregular  township  exterior,  or  other  controlling  boundary,  a  retrace- 

Closirig  error  of 
retrocemerit- 


Fig.  68. 


ment  will  be  initiated  at  the  nearest  identified  original  corner  on  the 
boundary,  following  out  the  record  courses  and  distances,  or  the 
equivalent  by  calculation,  setting  a  temporary  stake  for  each  missing 
corner  or  angle  point,  until  the  next  identified  original  corner  has 
been  attained,  where  a  final  temporary  stake  will  be  set  at  the  record 
distance  of  the  last  course  of  the  retracement.  The  closing  error  will 


RESTORATION  OF  LOST  CORNERS.          271 

then  be  determined  for  course  and  distance  from  the  last  temporary 
stake  to  the  objective  original  corner,  and  each  temporary  stake  will 
thereafter  be  adjusted  on  the  bearing  of  the  closing  error,  a  propor- 
tional amount  of  the  length  of  the  closing  error  equal  to  the  propor- 
tional part  of  the  distance  of  the  temporary  stake  from  the  initial 
point  of  the  retracement,  i.  e.,  the  particular  distance  to  be  measured 
at  any  temporary  stake,  on  the  bearing  of  the  closing  error,  is  to  the 
whole  length  of  the  closing  error  as  the  distance  of  the  particular 
temporary  stake  from  the  initial  original  corner  is  to  the  whole 
length  of  the  retracement.  Angle  points  and  intermediate  corners 
will  be  treated  alike. 

(e)   ORIGINAL  CONTROL. 

381.  Where  a  line  has  been  terminated  with  reference  to  a  meas- 
urement in  one  direction  only,  a  lost  corner  will  be  restored  by  refer- 
ence to  the  original  record  bearing  and  distance,  counting  from  the 
nearest  regular  corner,  the  latter  having  been  duly  identified  or 
restored.     Examples  will  be  found  where  lines  have  been  discon- 
tinued   at    the  intersection    with   large    meanderable    bodies    of 
water,  or  at  the  border  of  what  was  classed  as  impassable  ground. 

(/)  INDEX  CORRECTION  FOR  AVERAGE  ERROR  IN  ALINEMENT  AND  MEASUREMENT. 

382.  In  unusual  cases  where  a  retracement  has  been  made  of 
many  miles  of  the  original  lines,  between  identified  original  corners, 
and  there  has  been  developed  a  definite  surplus  or  deficiency  in 
measurement,  or  a  definite  variation  in  alinement,  characterizing 
the  original  survey,  it  will  be  proper  to  make  allowance  for  such 
average  " index  error."     Such  adjustment  will  be  taken  care  of 
automatically  in  all  cases  where  there  exists  a  suitable  basis  for 
proportional  measurement,  but  in  any  case  where  such  control  is 
lacking,  an  index  error,  if  conclusive,  will  be  made  use  of  by 
applying  the  determined  correction  to  the  record  courses  and  dis- 
tances.    If  there  is  not  conclusive  evidence  of  such  index  error  the 
record  courses  and  distances  will  be  allowed  to  prevail. 

SPECIAL   CASES. 

383.  Examples  of  special  cases  could  be  set  forth  almost  indefi- 
nitely,  but  without  bringing  out  important  new  principles.     In 
some  respects  the  treatment  of  a  large  number  of  special  examples 
would  serve  to  confuse  the  subject  by  seeming  to  warrant  certain 
procedure  as  a  general  rule  which  in  fact  would  not  be  proper  were 


272  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

the  conditions  altered;  the  latter  occur  in  an  infinite  variety. 
Ample  provision  has  been  made  for  the  United  States  surveyor  to 
call  upon  a  supervising  officer  for  advice  in  difficult  cases,  and  where 
necessary  the  latter  is  in  a  position  to  direct  the  surveyor  to  proceed 
with  additional  retracements  in  order  to  develop  any  data  which 
should  be  considered  before  a  decision  is  rendered.  In  trials  of 
boundary  suits  the  court  will  generally  consider  many  additional 
questions  besides  those  concerned  in  the  technical  problem,  and  in 
such  instances  an  academic  study  of  hypothetical  examples  might 
serve  to  cloud  the  real  issue.  It  would  be  beyond  the  purpose  of 
the  Manual  to  invade  the  realm  of  non-technical  matter  while 
attempting  to  lay  down  the  general  principles  involved  in  the 
restoration  of  lost  corners. 

384:.  In  all  unusual  instances,  where  on  account  of  manifest 
distortion,  or  through  extensive  obliteration  resulting  in  great 
distances  between  existing  corners,  or  otherwise,  the  evidence  of  a 
survey  can  not  be  identified  with  sufficient  certainty  to  enable  a 
suitable  application  of  the  various  rules  relating  to  the  restoration 
of  lost  corners,  the  surveyor  is  again  advised  to  report  the  facts  to 
the  proper  supervising  officer.  In  the  same  connection,  it  is  impor- 
tant that  the  surveyor  should  not  be  confused  with  the  notion  that 
he  is  required,  or  has  any  authority,  to  revert  to  the  principles 
relating  to  the  establishment  of  original  surveys  as  an  alternative  in 
such  cases.  The  methods  incident  to  resurveys,  as  outlined  in  the 
next  chapter,  are  designed  to  rectify  unusual  conditions  which  are 
widely  at  variance  with  the  representations  of  the  original  approved 
plat  and  field  notes. 

(0)   MISCELLANEOUS  CONTROL. 

385.  It  will  be  apparent  to  the  experienced  surveyor  that  actual 
field  conditions  do  not  always  furnish  the  basis  for  the  application 
of  the  rules  heretofore  set  forth,  and  while  developing  a  consistent 
theory  to  apply  in  unusual  cases  the  surveyor  will  at  once  note  that 
the  first  consideration  relates  to  a  more  or  less  arbitrary  limitation  of 
the  control  to  be  adopted.  No  definite  rule  can  be  laid  down,  except 
that  there  should  be  the  closest  possible  adherence  to  the  basic  exam- 
ples already  given  in  the  text.  The  methods  heretofore  outlined 
readily  harmonize  surveying  practice  with  legal  decisions  concerning 
the  restoration  of  lost  corners.  A  strictly  consistent  mathematical 
recovery  of  a  lost  corner,  not  based  upon  any  known  legal  decision, 
may  be  obtained  by  allowing  every  known  corner  within  a  reason- 


RESTORATION   OF  LOST  CORNERS.  273 

able  radius  to  enter  into  the  control,  each  original  corner  being  given 
a  weight  inversely  proportional  to  its  distance  from  the  missing 
corner,  and  though  the  principle  will  lead  to  the  same  result  in 
come  cases  as  by  the  methods  previously  outlined,  it  will  yield  a 
slightly  different  result  under  other  regular  circumstances.  For  the 
latter  reason  a  miscellaneous  control  based  upon  such  mathematical 
principle  will  not  be  adopted  except  as  specifically  approved  by 
the  proper  supervising  officer  after  due  consideration  of  the  facts 
in  regard  to  the  applicability  of  the  method  in  the  absence  of  a 
suitable  basis  for  a  regular  control. 

386.  Having  thus  safeguarded  the  application  of  the  following 
method,  the  problem  in  the  field  will  be  developed  by  a  series  of  re- 
tracements  each  beginning  at  an  accepted  corner,  thence  following 
out  the  record  courses  and  distances,  each  retracement  terminating 
at  a  temporary  stake  in  the  vicinity  of  the  objective  lost  corner. 
Each  stake  will  be  given  a  weight  inversely  proportional  to  the  dis- 
tance from  the  accepted  corner  to  which  it  is  related.  The  several 
temporary  stakes  will  then  be  combined ;  the  first  two  to  be  resolved 
into  a  point  on  the  line  between  them,  dividing  the  whole  distance 
into  two  parts  that  will  make  the  interval  from  either  stake  inversely 
proportional  to  the  weights  previously  assigned,  and  the  latter  point 
will  be  given  their  combined  weights.  The  last  point  will  then  be 
correlated  with  the  third  temporary  stake  on  a  similar  plan.  Three 
or  more  original  corners  will  thus  exercise  their  influence  upon  the 
final  resultant  position  for  the  corner  which  is  to  be  restored.  The 
result  will  be  the  same  no  matter  what  the  order  of  connecting  the 
temporary  stakes  may  be,  but  the  omission  of  any  element  of  the 
control  or  the  introduction  of  an  additional  original  corner  will  alter 
the  final  position.  The  field  of  influence  should  ^accordingly  be 
selected  with  a  view  to  obtaining  a  resultant  balanced  position  which 
can  not  be  materially  changed  by  the  introduction  of  other  known 
points  of  control. 


CHAPTER  VI. 

RESURVEYS. 

JURISDICTION. 

887.  Certain  important  considerations  are  involved  in  the  execu- 
tion of  Government  resurveys  of  an  entirely  different  character 
from  those  relating  strictly  to  the  making  of  original  surveys;  these 
considerations  present  matters  not  referred  to  in  Chapter  V.  There 
is  a  twofold  object  of  a  resurvey:  First,  the  adequate  protection  of 
existing  rights  acquired  under  the  original  survey  in  the  matter  of 
their  location  on  the  earth's  surface,  and,  second,  the  proper  marking 
of  the  boundaries  of  the  remaining  public  lands. 

388.  As  already  noted  in  Chapter  I,  the  Congress  has  authorized, 
under  certain  conditions,  the  re-marking  of  the  public-land  surveys. 
The  acts  relating  to  resurveys  contemplate  a  restoration  of  the 
corners  of  the  original  surveys  in  those  townships,  (a)  where  the 
obliteration  of  the  original  monuments  or  other  evidence  of  the 
position  of  the  original  lines  has  become  so  advanced  that  the  land 
boundaries  can  be  identified  only  through  extensive  retracements 
by  experienced  surveyors  of  the  General  Land  Office,  and  (6)  where 
field  investigation  shows  that  conditions  on  the  ground  disagree  with 
the  representations  upon  the  original  plat  to  such  an  extent  that  the 
land  boundaries  can  not  be  identified  positively  ifi  one  position  to 
the  exclusion  of  another,  in  consequence  of  which  said  plat  should 
be  disqualified  as  a  basis  for  the  disposal  of  remaining  public  land. 
While  the  Government  may  initiate  a  resurvey  in  the  absence  of  any 
application  therefor,  as  a  rule,  the  steps  preliminary  to  the  authori- 
zation of  a  resurvey  will  be  taken  by  the  settlers  interested  in  the 
land,  through  a  showing  of  facts  made  to  the  proper  supervising 
officer,  setting  forth  the  existing  conditions  with  respect  to  the 
original  survey  and  status  of  ownership  of  the  lands.1 

iSee  current  circular  governing  applications  for  resurveys. 

275 


276  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

389.  The  surveyor  is  advised  to  bear  in  mind  the  fact  that  in 
localities  where  resurveys  are  necessary  the  occasion  for  boundary 
disputes  is  ever  present;  he  should  accordingly  exercise  the  greatest 
care  in  his  technical  work  in  the  field  and  in  the  record  thereof,  so 
that  the  result  of  the  resurvey  shall  relieve  existing  difficulties  as 
far  as  possible  without  introducing  new  complications.     As  in  the 
case  of  original  surveys,  the  records  of  all  resurveys  must  form  an 
enduring  basis  upon  which  depends  the  security  of  the  title  to  all 
lands  acquired  thereunder,  and  the  field  notes  should  be  so  prepared 
that  under  the  test  of  the  closest  possible  scrutiny  at  all  times, 
present  and  future,  the  record  can  be  regarded  as  conclusive  in  the 
matter  of  the  location  of  such  rights. 

390.  The   General   Land   Office  has  exclusive  jurisdiction  over 
all  matters  pertaining  to  surveys  and  resurveys  affecting  the  public 
lands;  as  between  private  owners  of  lands  the  title  to  which  has 
passed  out  of  the  United  States,  final  determination  in  the  matter 
of  fixing  the  position  of  disputed  land  boundaries  rests  with  the  local 
court  of  competent  jurisdiction.     The  rules  of  procedure  laid  down 
by  the  General  Land  Office  to  guide  its  surveyors  in  the  re-marking 
of  lines  of  previous  surveys  are  intended  to  be  in  harmony  with  the 
leading  court  decisions  in  suits  involving  boundary  disputes,  and 
said  rules  should  be  so  applied  that  the  courts  may,  with  security, 
accept  without  question  the  boundaries  thus  determined  in  so  far 
as  they  represent  the  true  location  of  a  particular  tract  intended 
to  be  conveyed  by  a  patent.     Government  resurveys  are  under- 
taken   only  by  duly  appointed   United  States  surveyors  acting 
under  the  authority  of  the  Secretary  of  the  Interior  through  the 
Commissioner  of  the  General  Land  Office  and  under  the  immediate 
direction  of  subordinate  supervising  officers. 

LIMIT  OF  AUTHORITY  OF  SURVEYOR. 

391.  There  are   certain  questions  of  a   purely  judicial   nature 
involved  in  resurveys  of  every  description  where  the  decision  is 
to  be  reserved  to  the  General  Land  Office,  particularly  those  relating 
to  compliance  with  the  general  laws  in  respect  to  the  entry  of  the 
public  lands.     Thus  it  comes  within  the  realm  of  the  surveying 
process  to  identify  and  mark  out  on  the  ground  the  various  legal 
subdivisions  of  the  public  domain,  but  it  is  a  judicial  question 
beyond  the  function  of  the  surveyor  to  determine  whether  or  not 
specified  lands  have  been  duly  earned  under  a  certain  entry.     In 


RESURVEYS.  277 

the  resurvey  process  the  surveyor  will  determine  whether  or  not 
lands  embraced  within  a  claim  as  occupied  have  been  correctly 
related  in  position  to  the  original  survey,  and  where  the  demon- 
stration of  this  question  may  be  one  involving  more  or  less  uncer- 
tainty, as  is  often  the  case,  the  surveyor  will  examine  and  weigh 
the  evidence  relating  strictly  to  the  surveying  problem  involved, 
and  he  will  interpret  the  evidence  in  respect  to  its  effect  upon  the 
manner  in  which  the  resurvey  shall  be  executed  looking  to  the 
protection  of  the  valid  rights  acquired  under  the  original  survey. 
The  surveyor  has  no  authority  to  enter  into  any  agreements  looking 
to  the  exchange  of  one  subdivision  for  another,  or  to  bind  the  General 
Land  Office  in  this  particular. 

BONA  FIDE  RIGHTS  OF  CLAIMANTS. 

392.  In  order  to  carry  out  the  provisions  of  the  laws  relating  to 
resurveys,  the  surveyor  should  understand  fully  the  meaning  of 
the  words  "bona  fide  rights r  and  under  what  circumstances  it  will 
be  held  that  such  rights  have  been  impaired  by  a  resurvey.     In 
this  connection  attention  is  again  directed  to  the  clause  contained 
in  the  act  of  March  3,  1909  (35  Stat.,  845),  as  amended  by  joint 
resolution  approved  June  25,  1910  (36  Stat.,  884),  which  reads  as 
follows: 

"  That  no  such  resurvey  or  retracement  shall  be  so  executed  as  to 
impair  the  bona  fide  rights  or  claims  of  any  claimant,  entryman,  or 
owner  of  lands  affected  by  such  resurvey  or  retracement." 

The  rights  of  claimants  are  to  be  given  similar  protection  under 
the  provisions  of  the  act  of  September  21,  1918  (40  Stat.,  965). 

393.  It  will  be  understood  that  bona  fide  rights  are  those  acquired 
in  good  faith  under  the  law.     Eights  of  this  character  can  be  affected 
by  a  resurvey  only  in  the  matter  of  POSITION  or  LOCATION  on  the 
earth's  surface,  and  the  surveyor  will  be  concerned  only  with  the 
question  as  to  whether  lands  covered  by  such  rights  have  been 
actually  LOCATED  in  good  faith.    Other  questions  of  good  faith,  such 
as  priority  of  occupation,  possession,  continuous  residence,  value 
of  improvements,  and  cultivation,  when  considered  apart  from  the 
question  of  the  position  of  the  original  survey,  do  not  in  any  manner 
affect  the  problem  of  resurvey. 

It  is  evident  that  the  resurvey  must  afford  adequate  protection 
to  bona  fide  rights  vested  in  both  improved  and  unimproved  lands. 
In  the  final  determination  of  the  true  position  of  all  lands,  whether 


278  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

improved  or  unimproved,  in  the  absence  of  original  corners,  the 
necessity  for  more  or  less  flexibility  of  method  must  be  recognized, 
as  the  value  of  both  of  these  classes  of  lands  may  be  vitally  affected 
by  an  arbitrary  process  of  resurvey  which  is  rigid  in  its  application. 
Unimproved  lands,  however,  where  no  apparent  attempt  has  been 
made  on  the  part  of  the  owner  to  identify  the  same  under  their 
original  descriptions  (and  where  the  inherent  value  of  the  lands  in 
question  is  the  same),  are  not  necessarily  affected  in  the  same  manner, 
and  such  unimproved  lands  may  be  adjusted  to  a  position  found 
by  the  surveyor  to  be  conformable  to  adjoining  or  near-by  tracts, 
where  all  may  be  held  to  qualify  under  the  rule  of  acceptable  loca- 
tion. 

394.  The   question   arises  whether  the  technical  rules  for  the 
restoration  of  lost  corners  are  to  be  rigidly  applied  in  all  cases  regard- 
less of  their  effect  on  the  position  of  improvements,  or  whether  the 
position  of  all  improvements  is  to  be  accepted  without  question 
regardless  of  the  relation  or  irrelation  of  such  improvements  to  the 
existing  evidence  of  the  original  survey  and  to   the   description 
contained  in  the  entry.     Manifestly  these  opposite  extremes  are 
equally  unacceptable.     Somewhere  between  them,  therefore,  will 
be  found  the  basis  for  a  determination  of  the  question  as  to  when 
lands  so  improved  are  to  be  regarded  as  having  been  LOCATED  in 
good  faith  or  otherwise.     It  is  clear  that  no  definite  specific  set  of 
rules  can  be  laid  down  in  advance  for  the  determination  of  this 
question.     This  is  a  problem  the  solution  of  which  must  be  found 
on  the  ground  by  the  surveyor;  it  is  upon  his  judgment  primarily 
that  the  responsibility  for  a  determination  of  the  question  of  good 
faith  as  to  LOCATION  must  rest.     The  surveyor  may  err  in  his  judg- 
ment, but  once  this  question  is  settled  to  his  own  satisfaction,  the 
procedure  to  be  adopted  in  the  matter  of  the  application  of  resurvey 
rules  is  no  longer  in  doubt. 

395.  It  may  be  held  generally  that  an  entryman  has  located  his 
lands  in  good  faith  (referred  to  herein  as  an  acceptable  location  of 
a  claim  or  of  a  local  point),  when  it  is  evident  that  his  interpretation 
of  the  record  of  the  original  survey  as  related  to  the  nearest  existing 
corners  at  the  time  the  lands  were  located  (as  denned  by  his  fencing, 
culture,  or  other  improvements)  is  indicative  of  such  a  degree  of 
care  and  diligence  upon  his  part,  or  that  of  his  surveyor,  in  the  ascer- 
tainment of  his  boundaries,  as  might  be  expected  in  the  exercise  of 
ordinary   intelligence    under   existing   conditions.    From   this   it 


RESURVEYS.  279 

follows  that  lack  of  good  faith  is  not  necessarily  chargeable  against 
an  entryman  if  he  has  not  located  himself  according  to  a  rigid  appli- 
cation of  the  rules  laid  down  for  the  restoration  of  lost  corners,  where 
complicated  conditions  involve  a  double  set  of  corners,  both  of 
which  may  be  regarded  as  authentic;  or  where  the  nearest  existing 
corners  in  one  or  more  directions  are  an  excessive  distance  away; 
or  are  improperly  related  to  each  other  to  an  extraordinary  degree; 
or  where  all  evidences  of  the  original  survey  which  had  been  adopted 
by  the  entryman  as  a  basis  for  his  location  have  been  lost  before  the 
resurvey  is  undertaken.  Furthermore,  the  extent  of  recognition 
given  by  neighboring  claimants  to  a  local  point  used  for  the  control 
of  the  location  of  claims  very  often  carries  with  it  the  necessity  for 
a  consideration  by  the  surveyor  of  its  influence  in  the  matter  of 
the  acceptability  of  such  locations  under  the  foregoing  rule  of  good 
faith. 

396.  In  cases  involving  extensive  obliteration  at  the  date  of 
entry,  the  entryman  or  his  successors  in  interest  may  be  charged  with 
the  knowledge  that  the  boundaries  of  the  claim  will  probably  be 
subject  to  more  or  less  adjustment  in  the  event  of  a  resurvey,  and 
that  in  the  process  of  fixing  the  boundaries  of  groups  of  claims  a 
general  control  applied  to  all  must  be  favored  as  far  as  possible  in 
the  interest  of  equal  fairness  to  all  and  of  simplicity  of  resurvey. 
Even  in  the  presence  of  extensive  obliteration  of  the  original  survey, 
a  claim  which  manifestly  shows  that  no  attempt  has  been  made  to 
relate  the  same  in  some  manner  to  the  original  survey  can  not  gener- 
ally be  regarded  as  having  been  located  in  good  faith. 

397.  Cases  will  arise  where  it  may  be  evident  that  lands  have 
been  OCCUPIED  in  good  faith,  but  whose  boundaries  as  occupied  are 
clearly  in  disagreement  with  the  demonstrated  position  of  the  legal 
subdivisions  called  for  in  the  description.    Obviously  the  rule  of 
good  faith  as  to  location  can  not  apply,  and  relief  must  be  sought 
through  the  process  of  amended  entry  (act  of  Feb.  24,  1909,  35  Stat., 
645)  to  cover  the  legal  subdivisions  actually  earned,  rather  than 
through  an  alteration  of  the  position  of  established  lines.    This  is  a 
process  of  adjudication  rather  than  one  of  resurvey.    A  case  of  this 
character  should  be  regarded  as  an  "erroneous  location, "  in  pre- 
cisely the  same  manner  as  would  obtain  if  the  question  of  resurvey 
were  not  involved. 

398.  The  recognition  of  the  principle  that  the  restoration  of  a  cor- 
ner may  be  influenced  by  the  position  of  one  or  more  existing  claims 


280  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

warrants,  within  suitable  limits,  the  acceptance  of  an  unofficial  deter- 
mination, in  the  manner  hereinafter  stated,  which  would  not  neces- 
sarily agree  with  that  resulting  from  a  rigid  application  of  arbitrary 
rules  laid  down  for  the  restoration  of  lost  corners. 

GENERAL  FIELD  METHODS. 

399.  There  are  two  recognized  methods  of  making  Government 
resurveys — DEPENDENT   and   INDEPENDENT — and  in  general,  any 
field  condition  that  may  arise  can  be  taken  care  of  by  the  applica- 
tion of  one  or  the  other  method. 

400.  The  DEPENDENT  resurvey  is  designed  to  accomplish  a  restora- 
tion of  what  purports  to  be  the  original  conditions  according  to  the 
record,  based,  first,  upon  identified  existing  corners  of  the  original 
survey  and  other  recognized  and  acceptable  points  of  control,  and, 
second,  upon  the  restoration  of  missing  corners  by  proportionate  meas- 
urement in  harmony  with  the  record  of  the  original  survey.     This 
type  of  resurvey  is  applicable  to  those  cases  showing  fairly  concordant 
relation  between  conditions  on  the  ground  and  the  record  of  the  origi- 
nal survey.     Titles,   areas  and  descriptions   should  remain  abso- 
lutely unchanged  in  the  typical  dependent  resurvey. 

401.  The  INDEPENDENT  resurvey  provides  methods  adapted  to  con- 
siderable areas  of  public  land  where  the  original  survey  can  not  be 
identified  with  any  degree  of  certainty  in  accordance  with  the  repre- 
sentations of  the  approved  plat  and  field  notes,  and  where  the  pre- 
vailing conditions  are  such  that  strictly  restorative  processes,  when 
applied  as  an  inflexible  rule  between  existing  monuments  or  adopted 
corner  positions,  are  either  inadequate  or  lead  to  unsatisfactory  re- 
sults.   This  type  of  resurvey  provides  for  the  segregation  of  indi- 
vidual tracts  when  necessary,  or  a  conformation  of  individual  tracts 
to  the  subdivisions  of  the  resurvey  if  suitable.     These  processes  are 
found  to  be  more  flexible  in  their  application  than  those  of  the 
strictly  dependent  type,  but  at  the  same  time  they  duly  protect  all 
private  rights  which  have  been  acquired  upon  the  basis  of  the  origi- 
nal approved  survey  and  plat.     With  respect  to  the  identification  and 
description  of  the  public  lands  involved,  the  independent  type  of  re- 
survey  supersedes  the  record  of  the  original  survey.    This  will  be 
made  apparent  by  the  representations  of  the  approved  resurvey  plat. 

402.  The  basic  principle,  with  respect  to  the  protection  of  bona 
fide  rights,  involved  in  one  type  of  resurvey  is  identical  with  that 
of  the  other  type,  whether  dependent  or  independent;  they  are  both 


KESTJRVEYS.  281 

to  be  regarded  as  a  demonstration,  on  the  part  of  the  General  Land 
Office,  in  the  light  of  the  best  evidence  available,  by  means  of  the 
legal  subdivisions  of  a  dependent  resurvey  or  by  the  tract  segrega- 
tions of  an  independent  resurvey,  of  the  original  position  of  entered 
or  patented  legal  subdivisions  or  lots  included  in  the  original  de- 
scription when  related  to  the  original  survey. 

403.  The  necessity  for  both  types  of  resurvey  is  encountered  in 
the  field;  the  applicability  of  one  or  the  other  method  is  altogether 
a  question  depending  upon  local  conditions,  such  as  extent  of  oblit- 
eration, relative  harmony  of  identified  and  recognized  points,  and 
extent  of  disposals  by  the  Government.  These  questions  should  not 
be  judged  in  advance  of  a  comprehensive  field  examination. 

404:.  In  general,  a  preliminary  field  examination  will  be  required 
and  authorized  before  the  resurvey  is  to  be  undertaken. 

The  purpose  of  an  investigation  is  to  develop  the  extent  of  the 
obliteration  of  the  evidence  of  the  original  survey,  the  extent  of 
settlement,  the  agricultural  possibilities  of  the  township,  and  any 
other  information  from  which  the  necessity  for,  and  the  propriety 
of,  the  proposed  resurvey  may  be  determined. 

A  second  purpose  to  be  subserved  by  an  investigation  is  the 
assembling  of  sufficient  data  concerning  the  local  survey  conditions 
to  permit  a  proper  type  selection;  and  with  this  end  in  view  the 
examining  surveyor  should  investigate  and  report  upon  the  relative 
position  of  the  evidence  of  the  original  survey;  the  degree  to  which 
identified  points  are  concordant  or  the  reverse;  the  extent  to  which 
corners  discordantly  related  have  been  made  the  basis  of  claim 
locations;  the  presence  of  one  or  more  systems  of  unofficial  local 
surveys  which  have  been  recognized  and  adopted  by  the  claimants 
in  fixing  their  boundaries;  and  the  degree  to  which  conflicts  are  to 
be  anticipated. 

405.  The  proper  supervising  officer  will  provide  the  examining 
surveyor Vith  suitable  instructions  in  which  the  scope  of  the  exam- 
ination will  be  indicated  and  attention  will  be  directed  to  the  par- 
ticular considerations  which  should  receive  attention.  During  the 
progress  of  the  investigation  interested  parties  should  be  informed, 
upon  inquiry,  that  the  work  then  in  progress  is  merely  preliminary 
and  only  for  the  purpose  of  gaining  information,  and  that  if  resurvey 
is  ultimately  authorized  all  valid  rights  will  then  be  protected  as 
required  by  law. 

55465°— 19 19 


282  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

406.  The  examiner's  report  should  contain  definite  recommenda- 
tions concerning  the  type  of  resurvey  which,  in  his  judgment,  should 
properly  be  applied  in  view  of  the  prevailing  conditions. 

When  the  report  and  recommendations  of  the  examiner,  with 
those  of  the  supervising  officer,  have  been  received  by  the  General 
Land  Office,  the  situation  will  be  considered,  the  appropriate  type 
of  resurvey  will  bie  determined,  and  the  preparation  of  special  instruc- 
tions for  the  resurvey  will  be  authorized. 

407.  The  special  instructions,  which  must  of  necessity  be  based 
largely  upon  the  data  provided  by  the  examination,  will  indicate 
the  scope  of  the  work,  and,  regardless  of  whether  the  lands  are  to  be 
dependently  or  independently  resurvey ed,  the  necessary  retrace- 
ments  will  be  made  to  fix  the  outboundaries  of  the  township  or 
townships  designated  for  resurvey.     With  the  limiting  boundaries 
once  restored  so  as  to  protect  under  the  rules  already  laid  down  all 
existing  property  rights  in  the  adjoining  lands  not  to  be  resurvey  ed, 
the  plan  of  procedure  outlined  in  the  instructions  should,  under 
the  known  conditions,  produce  satisfactory  results,  and  adherence 
thereto  is  expected.     If,  however,  unforeseen  conditions  are  devel- 
oped in  the  progress  of  the  resurvey,  which  may  apparently  render 
the  special  instructions  inapplicable  or  likely  to  produce  incon- 
sistent or  unsatisfactory  results,  it  is  of  the  utmost  importance  that 
the  surveyor  suspend  further  monumentation  of  the  corners;  and 
after  such  additional  retracement  and  investigation  as  may  be  neces- 
sary to  a  proper  understanding  of  the  situation,  he  should  report  the 
facts  to  the  proper  supervising  officer  and  request  further  instructions. 

408.  During  the  progress  of  the  resurvey  the  surveyor  should 
advise  all  interested  parties,  as  occasion  and  opportunity  may  offer, 
that  the  resurvey  is  not  to  be  regarded  as  official  or  binding  upon  the 
United  States  until  duly  accepted  by  the  Commissioner  of  the  Gen- 
eral Land  Office,  as  provided  by  law,  and  that  no  contemplated 
alteration  in  the  position  of  improvements  or  claim  boundaries 
should  be  made  in  advance  of  the  official  acceptance  of  the  resurvey. 

THE  DEPENDENT  RESURVEY. 

GENERAL   CONTROL. 

409.  A  dependent  resurvey  is  an  official  re-marking  of  the  original 
lines  upon  a  plan  whereby  existing  evidence  of  the  original  survey 
is  given  primary  control  over  the  position  of  the  lines  to  be  reestab- 
lished.    A  certain  amount  of  flexibility  (as  hereinafter  described) 


RESURVEYS.  283 

is  allowable  in  the  dependent  resurvey  when  necessary  for  the 
protection  of  bona  fide  rights  of  claimants,  particularly  in  those 
cases  where  no  objection  is  found  to  adopting  a  point  acceptably 
located  under  the  rule  of  good  faith  already  laid  down,  when  only 
slightly  at  variance  with  the  theoretical  position  of  the  same. 

410.  In  theory  the  process  consists,  first,  in  the  retracement  and 
reestablishment  of  the  township  exteriors;  second,  the  identifica- 
tion of  all  existing  interior  corners  or  other  evidence  of  the  original 
survey;  and,  third,  the  determination,  by  a  suitable  field  procedure, 
of  the  theoretical  position  of  all  missing  corners  as  indicated  by  a 
proper  interpretation  of  the  record  of  the  original  survey  in  relation 
to  such  existing  evidence.    The  actual  field  process  may  be  varied 
to  some  extent  in  order  to  meet  local  conditions  or  to  suit  the  con- 
venience of  the  surveyor,  but  the  theoretical  position  finally  deter- 
mined must  be  identical  with  that  which  would  result  from  a  strict 
application  of  the  principles  of  proportional  measurement.    When 
this  has  been  accomplished,  attention  should  be  given  to  the  adop- 
tion, as  an  integral  part  of  the  resurvey  system,  of  corner  positions 
determined  by  the  evidences,  of  whatever  character,  of  acceptable 
claim  location.    Such  evidences  may,  for  convenience,  be  termed 
" collateral  evidence"  as  distinguished  from  direct  evidence  of  the 
original  survey. 

411.  The  process  of  the  dependent  resurvey  differs  in  scope  from 
that  applied  for  the  usual  restoration  of  one  or  more  lost  corners, 
and  the  rules  governing  a  resurvey  bring  into  consideration  in  a 
more  comprehensive  manner  the  position  of  recognized  land  bound- 
aries, in  the  absence  of  evidence  of  the  original  corners.    The  sur- 
veyor has  noted  the  detailed   instructions  set  forth  in  Chapter  V 
looking  to  the  identification  of  existing  evidence^  of  the  original 
survey  and  the  application  of  the  rules  of  proportionate  measurement 
for  the  determination  of  the  theoretical  position  of  lost  corners. 
These  rules  will  be  applied  in  the  dependent  resurvey  generally 
with  respect  to  the  township  as  a  unit,  wherein  the  means  of  identi- 
fication of  each  and  every  existent  corner  will  be  exhausted  and  the 
theoretical  position  determined  for  each  lost  corner.    The  former 
are  to  be   considered   as   fixed   points   (except  in   most   unusual 
cases)  and  may  be  monumented  at  any  time;  the  latter  will  be 
subjected  to  the  possible  influence  of  points  which  may  afterwards 
be  determined  to  be  acceptably  located  under  the  same  rule  of  good 
faith,  and  will  be  marked  only  as  temporary  points  until  this  ques- 
tion has  been  disposed  of. 


284  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

412.  A  complete  retracement  of  the  original  survey  will  be  made, 
based  upon  known  corners,  it  being  assumed  that  the  exterior 
boundaries  of  the  township  to  be  resurveyed  have  been  identified 
or  restored  under  the  rules  already  laid  down  in  Chapter  V,  and 
under  those  relating  to  the  acceptability  of  a  local  point  or  claim 
location.     It  is  not  usually  possible  to  follow  the  method  and  order 
of  procedure  shown  in  the  record  of  the  original  survey  (owing  to 
missing  corners),  but  the  complete  system,  of  lines  will  be  run  out  by 
preliminary  retracement,  usually  beginning  with  the  meridional 
lines  between  known  corners,  followed   by  the  latitudinal  lines 
between  known  corners,   noting  the  intersections  with  the  said 
meridional  lines.     The  surveyor  must  be  supplied  with  a  complete 
copy  of  the  record  of  the  original  survey,  and  temporary  reference 
stakes  may  be  set  on  the  meridional  lines  at  the  record  measurement 
for  each  corner  point. 

413.  The  preliminary  retracernents  will  lead  at  once  to  the 
identification  of  the  prominent  evidence  of  the  original  survey  and 
a  trial  calculation  will  follow  as  to  the  latitudinal  and  longitudinal 
adjustments  at  each  missing  corner,  to  suit  the  proportions  which 
may  be  derived  when  based  upon  these  known  corners.    A  second 
and  more  exhaustive  search  will  then  follow  within  the  zone  of  the 
probable  location  of  each  missing  corner  for  the  more  obscure  evi- 
dence of  the  original  survey.    At  this  stage  of  his  field  work  the 
surveyor  should  exhaust  every  possible  means  of  identifying  the 
existent  corners  of  the  original  survey.     In  many  respects,  the 
surveyor  will  be  compelled  to  devise  his  own  methods  as  the  actual 
field  conditions  seem  to  warrant,  and  his  skill  and  judgment  as  a 
surveyor  should  function  to  the  fullest  capacity. 

If  additional  evidences  of  the  original  survey  are  found  by  this 
process,  a  second  trial  calculation  will  then  be  made  as  to  the  lati. 
tudinal  and  longitudinal  adjustments  of  the  temporary  reference 
stakes  previously  set  at  each  missing  corner,  to  suit  the  proportional 
measurements  derived  from  all  of  the  known  original  corners — 
exactly  as  outlined  in  Chapter  V.  These  calculated  adjustments 
will  determine  the  theoretical  location  of  each  lost  corner  vrith 
reference  to  all  existing  evidence  of  the  original  survey. 

In  the  absence  of  other  considerations,  the  theoretical  points  thus 
determined  by  proportionate  measurement,  based  upon  existing 
original  corners,  are  fixed  to  a  mathematical  certainty,  and  when 
these  points  have  been  determined,,  the  evidence  of  the  original 


RESURVEYS.  285 

survey  and  the  record  thereof  have  served  their  primary  purpose. 
Then,  and  not  until  that  time,  is  the  surveyor  prepared  to  consider 
the  weight  of  such  collateral  evidence  as  may  be  available. 

414.  The  question  now  to  be  determined  is  whether  the  position 
of  the  lands  claimed,  occupied  or  improved  is  to  be  adopted  under 
the  rule  of  good  faith  as  to  location,  and  whether,  if  so  adopted,  the 
claims  thus  acceptably  located  can  all  be  properly  protected  by  the 
dependent  plan  of  resurvey.     If  the  position  of  any  claim 'fails  to 
qualify  under  the  said  rule  of  good  faith  it  may  be  disregarded  as  to 
the  effect  produced  thereon  by  the  plan  of  dependent  resurvey.     On 
the  other  hand,  if  these  claims  are  held  to  be  acceptably  located 
under  the  same  rule,  they  may  be  adopted  as  the  determining  factor 
in  the  position  of  the  missing  corner  or  corners;    and  if  the  claims 
are  in  such  concordant  relation  to  each  other  and  to  the  identified 
evidences  of  the  original  survey  as  to  receive  full  protection  by  the 
dependent  plan  of  resurvey,  the  surveyor  may  proceed  with  ful 
assurance  of  the  adequacy  of  the  plan.     Otherwise,  the  question  of 
other  processes  analogous  to  those  of  an  independent  resurvey  (as 
hereinafter  explained)  must  be  considered. 

If  two  or  more  claims  are  acceptably  located,  but  are  discordantly 
related  to  each  other  to  a  considerable  degree  (by  virtue  of  irregu- 
larities in  the  original  survey),  it  will  be  clear  that  the  general  plan 
of  dependent  resurvey  may  not  afford  protection  to  such  claims; 
whereupon  the  influence  thereof  must  be  rejected  in  favor  of  the 
theoretical  point  previously  determined  by  proportional  measure- 
ment. In  this  case,  as  before  stated,  some  other  process  must  be 
adopted  to  protect  the  acceptably  located  claims, 

415.  These  acceptably  located  points  for  the  missing  comers  will 
receive  all  the  authority  and  significance  of  an  identified  original 
corner,  and  when  the  influence  thereof  on  the  dependent  plan  of 
resurvey  has  been  combined  with  that  of  the  existing  original  corners 
previously  identified,  the  latitudinal  and  longitudinal  adjustments 
of  the  temporary  points  on  the  meridional  lines  may  be  made 
accordingly. 

416.  In  cases  of  distortion,  if  the  distorted  lines  are  to  be  adopted 
in  the  plan  of  dependent  resurvey,  it  should  be  remembered  that  the 
lengths  of  lines,  when  subject  to  double  proportion,  are  comparable 
only  when  reduced  to  cardinal  equivalents  or  to  equivalents  along 
the  direct  lines  between  the  nearest  existing  corners. 


286  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

417.  Many  situations  will  arise  where  it  will  be  manifest  to  the 
surveyor  that  it  is  better  to  accept  a  position  based  upon  local 
improvements  rather  than  to  disturb  satisfactory  existing  condi- 
tions.   The  surveyor  will  endeavor  to  avoid  disturbing  the  posi- 
tion of  locally  recognized  lines  when  such  action  may  adversely 
affect  improvements,  and  at  the  same  time  extreme  caution  will 
be  exercised  in  the  matter  of  adopting  local  points  of  control,  which 
when  accepted  must  be  given,  as  above  stated,  a  significance  similar 
to  that  of  an  original  corner  and  be  allowed  to  function  on  an  equality 
therewith.    The  acceptance  of  duly  qualified  and  locally  recognized 
points  of  control  should  aid  materially  in  obtaining  simplicity  of 
resurvey  and  avoid  the  need  for  special  metes-and-bounds  surveys 
(as  hereinafter  described),  which  would  differ  only  slightly  in  posi- 
tion from  the  regular  lines  of  the  resurvey.     In  this  manner  a  flexi- 
bility will  be  introduced  in  the  application  of  a  dependent  resurvey, 
at  least  to  the  point  of  protecting  satisfactory  local  adjustments. 

418.  The  surveyor  should  fully  understand  that  the  field  of 
influence  to  be  exercised  by  any  acceptable  location  must  be  re- 
stricted to  that  already  covered  in  a  larger  way  by  the  existing 
evidences  of  the  original  survey,  and  that  the  adjustive  process 
ia  of  more  or  less  local  application.     In  this  connection,  it  should 
be  noted  that  the  record  of  the  original  survey  can  not  be  abandoned 
in  favor  of  an  indiscriminate  adoption  of  property  corners,  all  or  a 
portion  of  which  fail  to  qualify  as  aforestated,  nor  is  it  to  be  assumed 
that  because  a  large  number  or  all  of  the  claims  within  a  township 
are  consistently  related  among  themselves  to  an  arbitrary  system 
of  control  which  is  itself  altogether  unrelated  to  the  original  survey, 
that  such  system  is  necessarily  to  be  adopted  as  the  basis  of  a  depend- 
ent resurvey. 

419.  Thus  where  bona  fide  rights,  as  defined  hereinbefore,  are 
found  to  have  been  definitely  established  with  reference  to  the 
location  of  lands  the  position  of  which  can  not  otherwise  be  fully 
demonstrated  by  existing  evidence  of  the  original  survey,  the 
surveyor  engaged  in  the  resurvey  will  reject  the  theoretical  point 
determined  by  the  primary  control  in  favor  of  a  near-by  duly  qualified 
corresponding  point,  the  position  of  which  has  been  agreed  upon 
by  the  adjoining  property  owners.     Such  a  point  may  be  recognized 
as  the  best  available  evidence  of  the  true  position  for  a  corner;  as 
previously  stated  its  acceptance  by  the  surveyor  confers  upon  the 


RESURVEYS.  287 

point  a  significance  similar  to  that  of  an  original  corner  position, 
and  thus  avoids  disturbing  satisfactory  local  adjustments.  Chief 
among  this  class  of  evidence  forming  the  basis  of  the  recognized 
position  of  land  boundaries  are  recorded  monuments  established 
by  local  surveyors,  duly  agreed  upon  by  the  interested  property 
owners;  the  position  of  boundary  fences  determined  in  the  same 
manner;  and  the  center  lines  of  public  roads  and  drainage  or  irriga- 
tion ditches,  when  intended  to  be  located  on  the  subdivisional 
lines  of  the  public-land  surveys.  The  local  record  in  these  cases, 
when  available,  may  furnish  the  connecting  link  to  the  previously 
identified  evidence  of  the  original  survey,  but  even  in  the  absence 
of  a  conclusive  record,  if  a  point  qualifies  as  above  outlined,  the 
presumption  is  strong  that  its  position  bears  satisfactory  relation 
to  the  original  survey  and  that  its  correctness  can  not  be  success- 
fully disputed.  Points  which  actually  qualify  as  aforestated  may 
be  accepted  as  the  best  available  evidence  of  the  true  position  of 
the  original  survey. 

420.  The  technical  record  of  the  resurvey  should  clearly  set 
forth  the  reasons  for  the  acceptance  of  a  local  point,  where  unofficial 
determinations  of  the  above  character  do  not  represent  actual  marks 
of  the  original  survey.     Such  recognized  and  acceptable  local  marks 
will  be  preserved,  and  described  in  the  record  of  the  resurvey.    New 
monuments  will  be  established  as  required,  in  addition  to,  but  with- 
out destroying  the  evidence  of,  the  local  marks. 

REESTABLISHMENT    OP   TRUE    LINES. 

421.  As  already  stated,  with  the  combined  control  of  the  depend- 
ent resurvey  fully  determined,  the  final  calculation  will  be  made 
as  to  the  latitudinal  and  Jongitudinal  adjustments  of  the  temporary 
reference  stakes  previously  set  at  the  remaining  missing  corners. 
The  final  calculations  will  be  based  upon  the  known  position  of  the 
corners  of  the  general  control  as  thus  adopted,  upon  the  plan  of 
proportionate  measurement,  all  as  provided  in  Chapter  V.    The 
result  of  this  process  balances  in  regular  proportion  the  differences 
between  the  measurements  shown  in  the  record  of  the  original  sur- 
vey and  those  derived  in  the  retracement.    Thus  the  true  lines  of 
the  dependent  resurvey  are  finally  determined  through  the  influ- 
ence exercised  by  the  identified  existent  corners  of  the  original 
survey  and  every  other  identified  call  of  the  record  thereof,  and 


288  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

such  other  collateral  evidence  of  the  position  of  recognized  land 
boundaries  as  may  be  properly  adopted  for  such  influence. 

4:22.  The  field  procedure  incident  to  the  running  and  measure- 
ment of  the  true  lines  of  the  dependent  resurvey  will  conform  to 
the  requirements  of  Chapter  II,  while  the  marking  of  lines  between 
corners  and  the  notation  of  objects  to  be  recorded  wi.ll  conform  to 
the  provisions  of  Chapter  III,  and  the  monumentation  of  the  survey 
will  comply  with  Chapter  IV.  The  technical  record  of  the  resur- 
vey will  be  broadened  to  show  the  relationship  between  the  original 
survey  and  its  reestablished  lines. 

428.  The  field  note  description  of  an  identified  or  accepted  corner 
will  be  introduced  into  the  technical  record  of  the  resurvey  at  the 
place  in  the  true  line  notes  where  the  position  for  the  corner  is  indi- 
cated as  having  been  attained.  The  record  will  embrace: 

(a)  A  complete  description  of  the  remaining  evidence  of  the  origi- 
nal monument ; 

(6)  A  complete  description  of  the  new  monument; 

(c)  A  complete  description  of  the  original  accessories  as  identified; 

(d)  A  complete  description  of  the  new  accessories; 

(e)  A  concise  statement  relating  to  the  recovery  of  a  corner  based 
upon  identified  line  trees,  blazed  lines,  items  of  topography,  or 
other  calls  of  the  field  notes  of  the  original  survey,  in  the  absence 
of  evidence  of  the  monument  or  its  accessories;  and, 

(/)  A  statement  of  fact  relating  to  the  relocation  of  an  obliterated 
monument;  or  a  statement  of  the  determining  features  leading  to 
the  acceptance  of  a  recognized  local  corner. 

424.  General  titles  (in  addition  to  the  regular  page  heading)  will 
be  inserted  in  the  field  notes  of  dependent  resurveys  to  indicate  the 
character  of  the  resurvey,  the  technical  record  of  which  follows. 
Such  titles  will  be  inserted  in  the  body  of  the  field  notes,  as  appro- 
priate, and  will  show  the  name  of  the  original  surveyor  and  the  year 
in  which  the  original  survey  was  executed;  as,  for  example: 

"  Eeestablishment  of  the  surveys  executed  by  John  B.  Smith, 
U.  S.  Surveyor,  in  1842," 

and  additional  memoranda  will  be  added  as  appropriate,  explana- 
tory of  the  method  of  control  adopted  in  the  restoration  of  one  or 
more  lost  corners. 

425.  In  addition  to  the  usual  showing  of  data  upon  the  township 
plat,  the  plat  of  a  dependent  resurvey  should  carry  a  memorandum 


RESURVEYS.  289 

for  the  information  of  the  public  to  the  effect  (modified  as  special 
circumstances  may  warrant)  that — 

"This  plat  of  the  resurvey  of  T. ,  R. ,  delineates  a  retrace- 

ment  and  reestablishment  of  the  lines  of  the  original  survey  as  shown 

upon  the  plat  approved (date),  in  their  true  original  position 

according  to  the  best  available  evidence  of  the  position  of  the  orig- 
inal corners;  all  differences  between  the  measurements  shown  on 
the  original  plat  and  those  derived  in  the  retracement  have  been 
distributed  proportionally  between  accepted  corners  in  accordance 
with  surveying  rules;  reference  will  be  made  to  the  original  plat 
for  the  showing  of  the  areas  and  more  detailed  descriptions  of  the 
various  smaller  subdivisions." 

ADDITIONAL  METHODS  FOR  THE   PROTECTION   OF  BONA  FIDE  RIGHTS. 

426.  Referring  to  those  cases  where  locally  recognized  corners 
are  discordantly  related  to  the  original  survey,  it  will  be  apparent 
that  such  corners  can  be  employed  only  for  the  determination  of 
the  boundaries  of  claims  where  bona  fide  rights  have  been  duly 
established  which  would  otherwise  be  impaired  by  the  resurvey 
under  the  same  rule  of  good  faith  in  the  matter  of  location.    Cases 
of  this  kind  are  found  to  be  decidedly  exceptional  in  the  townships 
where  dependent  resurveys  have  been  made,  and  such  situations  will 
be  given  particular  attention  in  the  preliminary  examination  and 
special  instructions.    In  those  instances  when  encountered,  provi- 
sion will  be  made  in  the  special  instructions  for  a  "metes-and- 
bounds "  survey,  as  hereinafter  outlined  under  the  general  subject 
of  "  independent "  resurveys,  unless  an  amendment  of  entry  in  con- 
formity with  the  lines  of  the  resurvey  will  answer  the  particular 
requirements  of  the  situation.    In  either  case  the  surveyor  will 
note  the  Manual  text  relating  to  metes-and-bounds  surveys  and 
amendment  of  entries  (see  sees.  434  to  452,  inclusive). 

EXAMPLE. 

427.  A  hypothetical  example  of  a  dependent  resurvey  follows  in 
the  text,  wherein  a  showing  of  typical  conditions  will  be  presented. 
In  this  connection  it  will  be  observed  that  the  application  of  the 
rules  for  the  execution  of  a  dependent  resurvey  is  generally  made 
with  respect  to  the  township  as  a  unit.     In  this  hypothetical  case 
it  is  presumed  that  a  sufficient  number  of  original  corners  can  be 
identified  to  enable  the  restoration  of  the  township  exteriors  resulting 
in  a  satisfactory  closure.    Upon  retracement  of  the  interior  lines, 
some  evidence  of  the  original  survey  is  developed,  also  certain 


290  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

recognized  and  acceptable  corners.  All  claims  are  found  to  be 
conformable. 

The  surveyor  will  proceed  with  the  complete  retracement  of  the 
interior  section  lines.  In  this  process  he  will  employ  instrumental 
methods  and  make  the  measurements  as  provided  in  Chapter  II. 
He  will  be  guided  by  the  suggestions  given  in  Chapter  V  in  regard 
to  the  search  for  evidence  of  the  original  survey,  and  beyond  that 
he  will  devise  his  own  methods  in  the  search  as  the  actual  field 
conditions  seem  to  warrant.  Temporary  reference  stakes  will  be 
set  where  the  original  corners  are  not  at  once  identified  (though 
the  use  of  local  reference  points  will  be  unobjectionable).  It  will 
be  assumed  that  a  single  system  of  reference  stakes  has  been  employ- 
ed, as  this  scheme  lends  itself  more  readily  to  theoretical  discussion, 
as  well  as  practical  utility  in  the  field,  and  allows  the  utmost  freedom 
as  to  the  order  in  which  the  retracements  are  made. 

Having  completed  the  reestablishment  of  the  township  exteriors 
and  the  retracement  of  the  interior  lines,  the  surveyor  will  be  con- 
cerned with  the  two  primary  considerations,  heretofore  discussed, 
which  it  is  his  duty  to  harmonize:  First,  the  restoration  of  what  the 
record  purports  to  be  original  conditions;  and,  second,  the  protection 
of  the  bona  fide  rights  of  claimants  in  the  matter  of  location.  The 
first  requirment  must  be  fulfilled  with  reference  to  the  evidence 
of  the  original  survey,  and  the  discovery  and  identification  of  actual 
original  corners  is  paramount,  bearing  in  mind  that  the  development 
of  a  single  additional  original  corner  adds  manifest  conclusiveness 
to  the  work.  These  identified  points  when  combined  with  those 
acceptably  located  constitute  the  general  control.  The  second 
item,  which  does  not  directly  affect  the  technical  procedure,  has 
been  fully  discussed  hereinbefore. 

KEY  TO   DIAGRAM,    FIG.    69. 

A.  Identified  original  corner. 

B.  Intersection  of  center  lines  of  public  crossroads,  intended  to  be  located  at  section 
corner  and  generally  so  recognized;  accepted  as  best  available  evidence  of  corner. 

C  and  D.  Identified  original  corners. 

E.  Corner  established  by  local  surveyor;  record  shows  proper  application  of  the 
method  of  double  proportionate  measurement;  generally  recognized  as  correct  posi- 
tion of  corner;  accepted  on  an  equality  with  an  identified  original  corner. 

F-M,  inclusive.  Identified  original  corners. 

N.  Same  as  B. 

O.  Identified  original  corner. 

P.  Intersection  of  mean  position  of  meridional  and  latitudinal  blazed  lines  through 
virgin  timber;  age  count  on  overgrowth  qualifies  for  date  of  original  survey. 

Q.  Restored  corner  based  upon  control  furnished  by  latitudinal  position  of  blazed 


RESURVEYS. 


291 


S.  Same  as  E. 

T.  Position  determined  by  location  of  improvements;  point  agrees  approximately 
with  the  theoretical  position  and  it  is  recognized  by  adjoining  claimants;  improve- 
ments would  be  adversely  affected  by  change  of  point. 

U.  Same  as  E. 

V  and  W.  Same  as  T. 


A 

/ 

j 

> 

^          / 

7 

t 

f 

. 

. 

19 

IS 

to 

Q 

-)*       ( 

P 

'  

--4 

U2-. 

J 

)  

---1 

D>- 

---I 

2-  _  -. 

£ 

14 

9 

7 

3 

1 

J  

---, 
/a 

7-  -- 

T  1 
13          ( 

5  

1 

U 

5  

1 

1-  < 

, 

>*--! 
A*     • 

5--- 

1 

J  

2 

17 

0-  -  - 

2 

/2          ^ 

I-  < 

)?  2 

2  

;...2 
s 

2 

)_-,- 

...i 

16 

9  

2 

3  

----? 

Q 

7---- 

-r-2 
^ 

6  : 

1 

8--- 

3 

|  

3 

2  

3 

3--- 

3 

\  

3 

5  

--.3 

j 

• 

k             f 

O     Employed  forgenefo/  con fro/. 
+     Theoretical  position. 

Fig.69. 

X.  Identified  original  corner. 

a.  Duly  restored  by  double  porportionate  measurement  and  thereafter  employed 
for  general  control  on  an  equality  with  an  identified  original  corner. 

b-n,  inclusive.  Theoretical  true  line  position,  duly  restored  by  single  proportionate 
measurement. 


292  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

METHOD. 

After  completing  all  retracements  and  having  determined  upon  the 
general  control  to  be  adopted,  as  indicated  in  the  diagram  and  accom- 
panying key,  the  true  lines  of  the  dependent  resurvey,  beginning  at 
the  southeast  corner  of  the  township,  will  be  reestablished  as  follows: 

SINGLE   PROPORTIONATE   MEASUREMENT. 

Lines:  A-B,  B-a,  A-C,  C-D,  D-E,  E-F,  F-G,  G-H,  H-I,  a-J, 
J-K,  K-L,  L-M,  and  M-I. 

DOUBLE   PROPORTIONATE   MEASUREMENT. 

Section  corners:  1,  f-N  and  b-F;  2,  f-N  and  c-S;  3,  O-P  and  d-X; 
4,  C-Q  and  b-F;  5,  C-Q  and  c-S ;  6,  C-Q  and  N-U;  7,  C-Q  and  d-X ;  8, 
g-S  and  b-F;  9,  U-n  and  d-X;  10,  U-n  and  Q-G;  11,  D-L  and  b-F; 
12,  D-L  and  V-i;  13,  D-L  and  W-j;  14,  D-L  and  d-X;  15,  D-L  and 
Q-G;  16,  h-X  and  b-F;  17,  h-X  and  V-i;  18,  h-X  and  W-j;  19, 
X-M  and  Q-G. 

INTERIOR   QUARTER-SECTION   CORNERS. 

All  missing  interior  quarter-section  corners  by  single  proportionate 
measurement  on  line  between  the  adjoining  section  corners  as  above 
determined. 

FIELD    DATA. 

The  retracements  develop  the  following  data  in  regard  to  the 
relative  position  of  certain  points  of  control  and  the  temporary  stakes: 

Beginning  at  f,  North,  40.00  chains,  set  temporary  stake;  80.00 
chains,  set  temporary  stake;  120.00  chains,  set  temporary  stake; 
160.00  chains,  set  temporary  stake;  200.00  chains,  set  temporary 
stake;  241.20  chains,  fall  90  links  W.  of  N.;  meridional  excess  f-N= 
1.20  chains=40  links  per  80.00  chains. 

Beginning  at  b,  West,  40.00  chains,  set  temporary  stake;  80.46 
chains,  fall  20  links  N.  of  temporary  stake  previously  set;  record  of 
original  survey  shows  length  of  line  80.22  chains;  continue  west, 
etc.,  to  F;  latitudinal  deficiency  b-F=84  links=14  links  per  80.00 
chains. 

Beginning  at  2  (temporary  stake),  East,  40.00  chains,  set  tempo- 
rary stake;  80.82  chains,  fall  44  links  S.  of  c;  record  of  original  sur- 
vey shows  length  of  line  79.90  chains;  run  west  from  temporary  stake 
at  2  on  similar  plan;  latitudinal  excess  c-S =66  links=22  links  per 
80.00  chains. 

CALCULATIONS. 

The  adjustments  of  the  temporary  stakes  to  true  line  position, 

' 


RESURVEYS. 

BETWEEN  SECTIONS  35  AND  36. 


293 


Memo. 

Course. 

Dis- 
tance. 

N. 

s. 

E. 

W. 

Retracement  f-1 

North 

80.00 

80.00 

Adjustment  at  1  for  meridional 

.40 

excess. 
Adjustment  at  1  fo'r  latitudinal 

*  * 

0.38 

deficiency,  80.46—  (80.22-0.  14-). 

True  line  f-1 

N  0°16'  E. 

80.40 

80.40 

.38 

Adjustment  at  f 

Too" 

.00 

Adjustment  at  1  

.40 

.38 

Adjustment  at  ^  sec.  cor.  (mean)  . 

.20 

.19 

BETWEEN  SECTIONS  25  AND  26. 


Adjustment  at  1  from  true  to 

0.40 

0.38 

temporary. 
Retracement  1-2., 

North. 

80.00 

80.00 

Adjustment  at  2  for  meridional 

.80 

excess. 
Adjustment  at  2  for  latitudinal 

0.70 

excess,  80.  82—  (79.90  -fO.22). 

80.80 

.40 

.70 

.38 

.40 

.38 

True  line  1-2  

N.  0°  14'  E. 

80.40 

80.40 

.32 

Adjustment  at  1 

.40 

•    - 

.38 



Adjustment  at  2.  . 

.80 

.70 

Adjustment  at  £  s&c.  cor.  (mean)  . 

1.20 
.60 



1.08 

.54 



BETWEEN  SECTIONS  23  AND  24. 


Adjustment  at  2  from  true  to 

0.80 

0.70 

temporary. 
Retracement  2-N 

North. 

81.20 

81.20 

Random  line  to  N  .  .           

East 

.90 

r 

0.90 

81.20 

.80 

.90 

.70 

.80 

.70 

True  line  2—  N 

N  0°  9'  E 

80  40 

80  40 

.20 

Adjustment  at  2. 

.80 

.70 

Adjustment  from  80.00  ch.  point 
on  random  to  N. 

1.20 

.90 

2.00 

1.60 

Adjustment  at  i  sec.  cor.  (mean)  . 

1.00 

.80 

294  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

BETWEEN  SECTIONS  25  AND  36. 


Memo. 

Course. 

Dis- 
tance. 

N. 

S. 

E. 

W. 

Retracement  b-1 

West. 

80.46 

80  46 

Random  line  to  temporary  stake 

0.20 

atl. 
Adjustment  at  1  temporary  to 

0.40 

0.38 

true. 

.40 

20 

38 

80.46 

.20 

.38 

True  line  b-1  

N.  89°  51'  W 

80.08 

.20 

80.08 

Adjustment  at  b  

.00 

.00 

Adjustment  from  80.00  ch.  point 

.20 

.46 

on  random  to  temporary  stake 
atl. 
Adjustment  at  1  temporary  to 

.40 

.38 

true. 

.40 

.20 

.38 

.46 

.20 

.38 

.20 

.08 

Adjustment  at  J  sec.  cor.  (mean)  . 

.10 

.04 

BETWEEN  SECTIONS  24  AND  25. 


c  to  random  line. 

0.44 

Retracennent  c-2  (reversed)  

West. 

80.82 

80.82 

Adjustment  at  2  tpTnporp.ry  to 

0.80 

0.70 

true. 

.80 

.44 

.70 

80.82 

.44 

.70 

True  line  c-2  

N.  89°  45'  W. 

80.12 

.36 

80.12 

Adjustment  from  80.00  ch.  point 

.44 

.82 

on  random  to  c. 
Adjustment  at  2  temporary  to 

.80 

.70 

true. 

1.24 

1.52 

Adjustment  at  ^  sec  cor  (mean) 

.62 

.76 

THE  INDEPENDENT  RESURVEY. 

428.  An  independent  resurvey  is  an  official  re-subdivision  of  the 
public  lands  distinct  from  the  original  survey  which  it  is  designed 
to  supersede.  The  independent  resurvey  is  accomplished  by  three 
distinct  steps: 

(a)  The  reestablishment  of  the  outboundaries  of  the  lands  subject 
to  resurvey,  following  the  method  of  a  dependent  resurvey; 


RESURVEYS.  295 

(6)  The  segregation  of  lands  embraced  in  any  valid  claim  where 
the  initial  steps  have  been  taken  looking  to  the  disposal  of  the  title 
of  the  United  States  based  upon  the  former  approved  plat;  and, 

(c)  New  exterior,  subdivisional  and  meander  lines  as  necessary, 
established  upon  a  new  regular  plan,  which,  for  every  purpose  of 
identification  and  description  of  the  public  lands  involved,  becomes 
the  prevailing  survey. 

REESTABLISHMENT   OF   OUTBOUNDARIES. 

429.  The  limiting  boundaries  of  the  lands  subject  to  independent 
resurvey  must  agree  with  the  previously  established  and  identified 
exterior  or  subdivisional  lines  of  the  approved  original  surveys.    In 
order  to  qualify  as  a  suitable  limiting  boundary  as  aforementioned, 
a  line  of  the  accepted  established  surveys  will  be  selected  which 
can  be  conclusively  identified  (by  existing  original  or  properly  re- 
stored corners)  in  one  position  to  the  exclusion  of  all  others  and 
which  by  its  known  position  adequately  protects  all  rights  (located 
in  good  faith  as  hereinbefore  defined)  based  upon  any  township  plat 
showing  subdivisions  of  the  public  lands  adjacent  to  said  boundary. 
Such  outboundaries  of  the  lands  to  be  resurveyed  by  the  independent 
process  must  necessarily  be  retraced  and  reestablished  in  their  true 
original  position.    The  lands  upon  one  side  of  such  outboundary  are 
to  be  re-subdivided  upon  a  new  plan,  while  upon  the  opposite  side  of 
such  line  the  original  subdivisions  are  to  be  strictly  maintained  and 
none  of  the  original  conditions  are  to  be  disturbed. 

430.  The  outboundaries  are  generally  selected  along  the  locus  of 
the  previously  established  township  exteriors  where  the  existing 
evidence  gives  positive  proof  of  the  location  of  the  original  survey, 
and  where  conditions  on  the  ground  are  harmoniously  related  to  the 
record  of  said  original  survey.     In  special  cases  certain  section  lines 
may  fully  qualify  as  suitable  lines  to  mark  the  limit  of  the  inde- 
pendent resurvey;  such  section  lines  will  then  be  duly  retraced  and 
reestablished  in  their  true  original  position.     Particular  attention 
will  be  given  to  this  very  important  subject  at  the  time  when  the 
field  examination  is  made  with  a  view  to  maintaining  the  original 
survey  as  far  as  consistent. 

431.  In  those  cases  where  a  proper  limiting  boundary  can  not  be 
secured  without  involving  the  necessity  for  the  inclusion  in  the 
group  of  a  greater  number  of  townships  than  administratively  prac- 
ticable to  execute  in  one  assignment,  the  necessity  may  arise  for  the 


296  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

extension  of  tract  segregations  (as  hereinafter  outlined)  into  a  town- 
ship ungrouped  for  resurvey.  In  such  cases,  under  specific 
authority  of  the  General  Land  Office,  any  tract  found  to  extend 
across  such  group  outboundary  will  be  segregated  in  full,  whether 
or  not  the  tract  was  originally  described  as  in  the  township  to  be 
resurveyed,  and  the  necessary  steps  will  thereupon  be  taken  by  the 
General  Land  Office  in  the  matter  of  suspension  of  the  lands  in  the 
adjoining  township  from  further  disposal  and  of  additional  investi- 
gations with  a  view  to  a  resurvey  of  all  or  a  portion  of  the  said 
adjoining  township.  (See  second  rule,  sec.  445.) 

432.  The  special  instructions  will  show  specifically  what  lines 
have  been  selected  to  limit  the  independent  resurvey,  and  the  sur- 
veyor engaged  in  the  execution  of  such  resurvey  will  proceed  with 
the  retracement  and  reestablishment  of  said  outboundaries  as  a  con- 
dition precedent  to  beginning  the  independent  resurvey. 

433.  Where  the  new  lines  of  the  independent  resurvey  are  not  to 
be  initiated  or  closed  upon  the  restored  original  corners  of  the  rees- 
tablished outboundaries  of  the  independent  resurvey,  said  restored 
corners  will  be  marked  only  with  reference  to  the  township,  range 
and  section  to  which  they  will  thenceforth  relate,  and  new  regular 
corners  of  minimum  control  will  be  established  as  necessary  to  govern 
the  lines  of  the  independent  resurvey,  all  as  provided  in  sec.  164, 
Chapter  III.     During  the  preliminary  stages  of  the  resurvey  there 
will  often  be  more  or  less  doubt  as  to  whether  an  old  corner  will  retain 
its  former  control  or  will  have  to  be  altered,  and  until  this  uncer- 
tainty has  been  removed  the  marking  of  a  corner  and  its  accessories 
should  be  deferred.     The  monumentation  will  follow  the  final  deter- 
mination of  the  future  significance  of  each  point.     Where  an  old 
point  is  to  be  perpetuated  merely  to  control  the  former  alinement, 
but  not  the  corner  of  a  subdivision,  its  future  significance  will  be  that 
of  an  "angle  point"  only  and  the  monument  and  its  accessories  will 
be  marked  accordingly. 

METES- AND-BOUNDS    SURVEY    OF    PRIVATE   CLAIMS. 

434.  After  the  reestablishment  of  the  outboundaries  of  the  lands 
subject  to  independent  resurvey  has  been  accomplished  in  accord- 
ance with  the  requirements  of  the  special  instructions,  the  surveyor's 
attention  will  be  directed  to  the  segregation  or  marking  out  of  all  duly 
entered,  selected,  reserved  (in  certain  cases),  granted,  or  patented 


RESURVEYS. 

lands  whose  description  may  be  based  upon  the  former  approved  plat, 
and  which  can  not  be  conformed  to  the  lines  of  the  resurvey. 

435.  A  status  diagram  will  be  furnished  to  the  surveyor  showing 
all  patented  lands,  valid  entries,  school  sections,  and  other  land 
grants,  and  all  other  disposals,  reservations,  or  selections  of  lands 
whose  position  and  description  are  based  upon  the  original  survey 
and  plat,  and  whose  boundaries  can  not  legally  be  disturbed.     In 
every  case  the  various  tracts  shown  upon  the  status  diagram  will 
be  protected  either  by  individual   umetes-and-bounds"  survey  or 
by  the  assignment  of  appropriate  subdivisions  of  the  resurvey  in 
case  the  latter  lines  (new  section  lines,  or  center  lines  of  sections 
or  quarter  sections)  are  found  to  coincide  or  approximately  agree 
with  the  boundaries  of  said  tracts. 

436.  It  is  not  to  be  understood  that  the  metes-and-bounds  survey 
of  private  claims  must  be  completed  before  beginning  the  projection 
of  the  new  lines  of  the  independent  resurvey.     It  has  merely  been 
deemed  logical  to  consider  the  subject  of  the  tract  segregations  in 
advance  of  the  question  of  the  establishment  of  new  lines.    The  fact 
is  that  surveyors  will  find  it  expedient  to  carry  both  branches  of  the 
survey  along  together  in  the  locality  of  the  camp  or  other  field  head- 
quarters. 

437.  The  jurisdiction  of  the  General  Land  Office,  the  limit  of  the 
authority  of  the  surveyor,  and  the  bona  fide  rights  of  claimants, 
where  entered  or  patented  lands  are  involved,  remain  absolutely  the 
same  whether  the  resurvey  is  to  be  made  upon  the  dependent  or 
independent  plan.     Thus  where  the  independent  type  of  resurvey 
has  been  adopted  as  more  feasible,  identified  corners  of  the  original 
survey  in  the  immediate  vicinity  of  lands  to  be  segregated  will  be 
employed  for  the  control  of  the  location  of  such  lands?    The  question 
of  the  good  faith  of  the  entrymaii  will  in  every  case  be  fully  con- 
sidered, as  previously  outlined  in  this  chapter,  and  where  the  evi- 
dence of  the  original  survey  is  so  obliterated  that  a  charge  of  a  lack 
of  good  faith  can  not  be  brought  against  an  entrymaii  whose  claim, 
boundaries  may  differ  from  a  theoretical  location  determined  by 
more  rigid  surveying  rules,  the  position  of  the  improvements  is  to  be 
regarded  as  the  best  available  evidence  of  the  original  position  of 
the  claim,  and  the  same  will  be  employed  as  far  as  consistent  for  the 
control  of  the  location  of  the  boundaries  of  such  claim. 

438.  Where  there  is  sufficient  evidence  of  the  original  survey,  the 
identification  of  the  areas  to  be  segregated,  resulting  from  the  sub- 

55465°— 19 20. 


298  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

division  of  the  original  sections,  will  proceed  in  accordance  with  the 
provisions  of  Chapters  III  and  V,  and  every  corner  or  angle  point 
of  each  tract  as  thus  located  will  be  marked  upon  the  ground. 

489.  Where  the  surveyor  can  not  point  out,  by  suitable  identi- 
fication of  the  original  surveys,  the  definite  location  of  an  entry 
"based  upon  the  former  approved  plat,  the  claimant  or  owner  of  such 
lands  will  be  consulted  as  to  the  position  of  his  boundary  lines.  The 
boundaries  of  the  private  claim,  so  determined,  will  be  fixed,  as 
between  the  private  and  public  lands,  subject  to  the  official  accept- 
ance of  the  resurvey.  Where  dispute  is  encountered  in  regard  to 
the  adjustment  of  the  line  between  adjoining  patented  tracts,  each 
acceptably  located  under  the  rules  already  laid  down,  which  can 
not  be  reconciled  or  suitably  disposed  of  by  surveying  process,  the 
tracts  will  be  surveyed  in  conflict,  as  hereinafter  provided,  and  so 
shown  on  the  resurvey  plat;  the  questions  arising  out  of  such  conflict 
will  be  given  administrative  review  with  the  field  notes  of  the 
resurvey. 

440.  The  owner  of  an  unidentified  claim  will  be  called  upon  to 
indicate  the  boundary  lines  thereof  if  possible,  and  in  this  connec- 
tion, should  occasion  arise,  the  surveyor  will  explain  the  manner  of 
adjusting  differences  between  adjoining  claims  and  what  will  con- 
stitute an  acceptable  location  of  a  claim.     The  latter  condition 
demands  a  form  agreeing  with  the  original  entry,  approximately 
regular  boundaries,  an  area  not  widely  inconsistent  with  that  shown 
upon  the  original  plat,  and  a  location  as  nearly  correct  as  may  be 
expected  from  the  existing  evidence  of  the  original  survey,  without 
overlapping  into  an  adjoining  township  not  subject  to  resurvey, 
except  as  provided  in  sec.  431.     In  every  case  where  the  out- 
boundaries  of  the  lands  subject  to  ''independent  resurvey"  have 
been  reestablished  by  the  "dependent"  or  "restorative"  plan,  the 
subdivisions  of  a  tract  situated  and  originally  described  as  along  or 
upon  the  opposite  sides  of  such  outboundary  must  agree  with  the 
line  reestablished  and  harmonize  in  relative  position. 

441.  In  the  execution  of  an  independent  resurvey,  therefore, 
the  identity  of  each  tract  to  be  segregated  therein  or  indicated 
by  conformation  to  the  lines  of  the  resurvey,  whether  patented 
or  unpatented,  must  be  maintained,  and  the  surveyor  will  not  be 
allowed  to  change  materially  the  configuration  of  a  tract  as  shown 
by  its  original  description  in  order  to  indemnify  the  owner  thereof 
against  deficiencies  in  area,  to  eliminate  conflicts  between  entries, 


RESURVEYS.  299 

or  for  any  other  purpose.  If  improvements  have  been  located  in 
good  faith,  the  segregation  survey  should  be  so  executed,  or  the 
conformation  to  the  lines  of  the  resurvey  so  indicated,  as  to  cover 
as  nearly  as  possible  these  improvements  and  at  the  same  time 
maintain  substantially  the  form  of  the  entry  as  originally  described. 
No  departure  from  this  rule  will  be  allowed. 

442.  The  question  of  amendment  of  entries  for  the  purpose  of 
permitting  adjustments  in  terms  of  the  resurvey  involving  lands 
not  included  within  the  original  tract  is  a  matter  for  the  adjudica- 
tion of  the  General  Land  Office  after  the  resurvey  has  been  accepted 
and  the  plats  thereof  filed  in  the  local  land  office. 

443.  In  case  of  absentee  owners  an  attempt  should  be  made  to 
establish  communication,  if  necessary,  in  order  that  the  claimant 
may  point  out  the  lands  subject  to  a  rnetes-and-bounds  survey.     If 
the  owner  can  not  be  found  and  thero  is  no  visible  indication,  such 
as  a  boundary  fence,  of  the  location  of  the  limits  of  a  claim,  the 
surveyor  will  exercise  the  alternative  of  locating  the  claim  from 
the  nearest  original  point  of  control  or  from  a  point  of  a  neighboring 
claim,  or  of  assigning  to  the  entered  or  patented  lands  the  appropri- 
ate subdivisions  of  the  resurvey,  all  subject  to  the  principles  here- 
inbefore set  forth.     The  controlling  factors  in  such  locations  will  be 
based  upon  the  individual  and  neighborhood  improvements  (such 
as  buildings,  wells,  springs  of  water,  cultivated  lands,  public  roads, 
fences,  corners  of  recognized  private  surveys,  etc.)  which  may  indi- 
cate the  evident  intention  of  the  entryman  or  patentee  as  to  the 
position  of  his  land. 

444.  Each  non-conformable  valid  claim  in  a  township  will  be 
given  a  serial  tract  number,  commencing  with  No.  37  in  the  smallest 
numbered  and  entered  section  of  the  original  plat,   progressing 
through  the  township  in  the  order  in  which  lots  and  sections  are 
numbered.     A  tract  number  will  be  used  but  once  in  a  township, 
and  if  any  tract  lies  partly  in  two  or  more  townships  subject  to 
resurvey  the  number  applied  to  the  tract  in  the  first  township 
resurveyed  will  not  be  used  for  other  tracts  in  the  adjoining  town- 
ship. 

445.  The  following  rules  will  be  observed  in  the  execution  of  the 
metes-and-bounds  survey  of  all  specially  designated  tracts: 

1st.  Each  claim,  acceptably  located,  but  at  variance  with  the  lines 
of  the  resurvey,  will  be  surveyed  and  monumented  at  each  angle 
point. 


300  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

2d.  Where  a  portion  of  a  claim  is  originally  described  as  in  a  town- 
ship not  subject  to  resurvey,  such  portion  of  the  claim  will  not  be 
surveyed  by  metes  and  bounds,  provided  the  limiting  boundary  is 
found  to  qualify  as  set  forth  in  sec.  429.  The  portion  of  the  claim 
originally  described  as  in  the  township  to  be  resurveyed  should 
ordinarily  be  defined  in  a  position  (either  by  segregation  or  confor- 
mation to  the  lines  of  the  resurvey)  which  is  properly  related  to  the 
identified  or  restored  corners  on  the  limiting  boundary.  (See 
sec.  431.) 

3d.  Where  the  boundaries  of  a  claim  are  unacceptably  located  as 
pointed  out  by  the  claimant,  the  surveyor  will  proceed  with  a  proper 
survey  of  the  tract  in  accordance  with  rules  already  stated  which 
will  result  in  a  suitable  relation  to  the  original  survey,  and  the  corners 
of  the  tract  as  thus  located  will  be  monumented.  If  the  claimant 
protests  against  such  location,  the  surveyor  will  request  that  the  pro- 
test be  made  in  writing  (to  be  submitted  with  the  returns  of  the  re- 
survey),  and  will  thereupon  make  an  accurate  connection  with  the 
corners  of  the  claim  as  unacceptably  located,  to  be  made  the  subject 
of  a  complete  report  by  the  surveyor  in  his  field  notes,  reviewing 
the  facts  with  reference  to  the  question  of  location.  As  a  further 
protection  to  an  entryman  thus  unacceptably  located  see  sec.  455. 

4th.  Where,  through  a  compliance  by  the  surveyor  with  the  general 
rules  above  laid  down,  the  metes-and-bounds  segregation  of  a  claim 
(or  the  conformation  thereof  to  the  lines  of  the  resurvey)  within  the 
field  of  an  independent  resurvey  (or  the  related  subdivisions  within 
the  field  of  a  dependent  resurvey)  fails  to  cover  any  or  all  of  the 
lands,  occupied,  improved  or  claimed  by  the  entryman,  patentee 
or  present  owner,  and  the  latter  indicates  a  desire  to  amend  his 
entry,  a  full  report  will  be  made  by  the  surveyor  in  his  field  notes, 
describing  therein  the  subdivisions  actually  occupied  and  sought  to 
be  acquired  under  the  amended  entry,  but  which  are  not  covered 
by  the  tract  as  surveyed,  all  looking  to  the  protection  of  the  title  to 
the  lands  actually  earned.1 

5th.  Where  it  so  happens  that  the  regular  quarter-quarter  sections 
embraced  within  a  claim  fall  in  approximately  the  same  position  as 
the  regular  quarter-quarter  sections  of  the  resurvey,  and  the  entry- 
man or  patentee  indicates  a  desire  to  conform  his  claim  to  the  re- 
survey,  and  no  apparent  objection  is  found  by  the  surveyor,  the 
facts  will  be  stated  in  the  field  notes,  and  the  claim  will  be  so  indi- 

1  See  current  circular  relating  to  amendment  of  entries. 


RESURVEYS.  301 

cated  upon  the  resurvey  plat.  Under  this  circumstance  the  metes- 
and-bounds  survey  of  the  tract  will  be  omitted.  However,  where 
any  tract  whose  original  description  includes  any  fractional  lot,  or 
where  any  part  of  a  tract  falls  upon  any  fractional  lot  of  the  resurvey, 
the  tracts  will  be  segregated  as  a  whole  by  metes-and-bounds  survey, 
even  though  some  or  all  of  the  lines  of  the  tract  may  coincide  with 
certain  subdivisional  lines  of  the  resurvey. 

6th.  Conflicting  tracts,  each  acceptably  located,  will  be  surveyed 
and  monumented,  and  conflict  shown  upon  the  resurvey  plat. 
Each  intersection  of  conflicting  boundaries  will  be  determined 
upon  the  ground  and  recorded  in  the  field  notes. 

7th.  The  angle  points  of  a  tract  will  be  designated  by  serial  num- 
bers beginning  with  No.  1  at  the  northeast  corner,  and  proceeding 
around  the  claim,  running  westerly  from  the  initial  corner.  An  angle 
point  may  be  common  to  one,  two,  three  or  four  tracts,  and  will  be 
monumented  and  marked  as  provided  in  Chapter  IV;  as  for  example: 

r«3  T26N     R'7E  T26NRI7E 

TR  37  S  14  - 

AP 


AP     4 
TR  38 


AP       I 
TR   45 


AP     2  AP      I 

TR  46  TR    38 


AP    2 
TR  37 


•919  1919 

8th.  No  accessories  will  be  required  with  the  monuments  at  the 
angle  points  of  the  metes-and-bounds  survey. 

446.  The  proper  supervising  officer  will  furnish  the  surveyor 
with  an  abstract  of  the  valid  entries,  selections,  reservations,  patents, 
and  grants,  based  upon  the  original  plat  of  any  township  (or  portion 
thereof)  subject  to  resurvey,  and  the  said  resurvey  can  not  be  re- 
garded as  complete  until  each  and  every  claim  described  in  said 
abstract  of  entries  (and  shown  on  the  status  diagram)  as  in  the  town- 
ship to  be  resurveyed  has  received  full  protection  in  the  matter 
of  location.    Aside  from  those  disposals  described  as  in  the  township 
to  be  resurveyed,  there  will  also  be  furnished  to  the  surveyor,  as  a 
matter  of  information,  the  status  of  all  claims  in  the  adjacent  sec- 
tions of  all   adjoining  townships  ungrouped   for  resurvey.     The 
abstract  will  be  included  with  the  other  data  to  accompany  the  writ- 
ten special  instructions  providing  for  a  resurvey. 

447.  The  field  notes  of  the  metes-and-bounds  survey  of  each 
valid  claim  will  be  preceded  by  a  copy  of  the  abstract  of  entry 
thereof.    A  brief  statement  will  then  follow  in  each  instance  (or 


302  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

with  suitable  reference),  concerning  the  principal  factors  controlling 
the  location  of  the  particular  tract,  and  whether  or  not  the  claimant 
was  consulted,  or  communicated  with,  in  the  matter  of  the  identifi- 
cation of  the  boundaries  of  his  claim.  The  statement  should  be 
clear  as  to  whether  the  location  of  a  claim,  shown  either  as  a  tract 
segregation  or  as  conforming  to  the  lines  of  the  resurvey,  was 
controlled  by  improvements  alone,  or  by  one  or  more  identified 
corners  of  the  original  survey,  nearby  or  remotely  located,  or  by  its 
relation  to  adjoining  tracts.  In  case  all  of  the  tract  segregations 
within  a  township  can  be  covered  by  one  general  statement,  the  same 
should  appear  at  the  beginning  of  the  field  notes  of  the  metes-and- 
bounds  surveys.  The  field  notes  should  be  made  to  account  for 
each  and  every  tract  shown  upon  the  status  diagram. 

448.  All  claims  should  be  accounted  for  on  the  resurvey  plat, 
and  all  will  be  shown  either  as  segregated  tracts  or  as  conforming  to 
the  lines  of  the  resurvey,  as  the  case  may  be,  with  outline  indicated 
by  heavy  black  lines.    An  exception  to  this  rule  will  be  made  in 
those  rare  cases  where  all  the  claims  within  a  township  have  been 
conformed  to  the  lines  of  the  resurvey  under  their  original  description, 
in  which  event  a  statement  may  be  made  on  the  margin  of  the  plat 
that— 

* '  All  claims  originally  described  as  in  this  township  are  intended  to 
conform  to  the  lines  of  the  resurvey  under  their  original  description." 

449.  As  a  further  safeguard  that  the  returns  of  independent 
resurveys  may  be  conclusive  in  the  matter  of  the  significance  of 
the  tract  segregations,  the  plats  thereof  will  show  a  statement  that — 

4 '  All  tract  segregations  shown  hereon  represent  the  position  and 
form  of  said  tracts  under  the  original  description  as  referred  to  the 
original  survey,  located  as  such  on  the  ground  according  to  the  best 
available  evidence  of  their  true  position.'* 

450.  The  above  statement  will  be  modified  if  one  or  more  of  all 
the  claims  shown  on  the  status  diagram  are  conformed  to  the  lines  of 
the  resurvey,  either  under  the  original  description  or  by  different 
legal  subdivisions,  as  follows: 

' l  All  tract  segregations  shown  hereon  and  all  other  claims  shown  to 
conform  to  the  lines  of  the  resurvey.  whether  by  the  original  or  new 
legal  subdivisions,  represent  the  position  and  form  of  said  tracts  un- 
der the  original  description  as  referred  to  the  original  survey,  located 
as  such  on  the  ground  according  to  the  best  available  evidence  of 
their  true  position . " 


RESURVEYS.  303 

451.  The  projection  and  measurement  of  the  lines  of  the  metes- 
and-bounds  survey  and  the  technical  record  in  respect  to  the  same 
will  conform  to  the  usual  practice  in  regular  surveys.    While  the 
mapping  of  important  items  of  topography  and  valuable  permanent 
improvements  will  be  given  attention  with  regard  to  this  feature  of 
the  resurvey  plat,  yet  it  will  be  apparent  that  the  amount  of  data  to 
be  shown  in  connection  with  the  metes-and-bounds  surveys  makes 
it  impossible,  at  the  usual  scale,  to  show  objects  of  little  relative 
importance.     This  class  of  memoranda  taken  during  the  progress  of 
the  work  will  not  be  required  in  the  field  notes  of  metes-and-bounds 
surveys. 

452.  At  least  one  angle  point  of  each  tract  survey  will  be  definitely 
connected  with  one  of  the  regular  corners  of  the  resurvey,  and  where 
lines  of  claims  are  intersected  by  lines  of  the  resurvey  a  connection 
will  be  made  from  the  point  of  intersection  to  the  nearest  claim  cor- 
ner and  recorded  in  the  field  notes  of  the  regular  section  line.     The 
latter  will  be  considered  a  satisfactory  connection  to  all  adjoining 
claims  located  within  the  interior  of  either  section.     Where  an  ex- 
tensive system  of  tract  segregations  has  been  surveyed,  the  interior 
tracts  of  the  block  will  not  require  individual  reference  connections. 
The  establishment  of  closing  corners  on  the  regular  line  when  entering 
or  leaving  public  land  will  conform  to  the  general  practice  in  this 
respect  as  provided  in  sec.  191,  Chapter  III. 

THE   PROJECTION    OP   NEW   LINES. 

453.  The  peculiar  conditions  of  the  situation  which  necessitate 
an  independent  resurvey  render  it  impossible  to  formulate  general 
rules  suited  to  all  cases.     Experience  has  demonstrated  the  neces- 
sity for  giving  deliberate  attention  to  the  unique  problems  of  subdi- 
vision which  are  to  be  found  in  each  definite  example.    The  general 
practice  is  to  secure  a  surveyor's  report  of  the  actual  conditions 
involved  in  a  particular  independent  resurvey,  upon  consideration 
of  which  there  may  be  devised  the  best  plan  for  a  re-subdivision  of 
the  .vacant  public  lands,  and  the  latter  will  be  set  forth  in  the  special 
instructions.    The  possibility  of  placing  the  regular  lines  of  the 
independent  resurvey  so  as  to  obtain  maximum  agreement  with  the 
position  of  the  boundaries  of  conformable  claims  will  be  fully  con- 
sidered with  a  view  to  eliminating  or  reducing  the  necessity  for 
tract  Segregations,  if  possible,  where  this  can  be  accomplished  in 
harmony   with   the   rules   previously   outlined.     The   examiner's 


304  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

recommendations  in  these  matters  should  be  explicit  and  responsive 
to  his  special  advantages  in  the  opportunity  of  working  out  the  tech- 
nical problem  while  on  the  ground. 

454.  A  problem  involving  the  re-subdivision  of  vacant  public 
lands,  as  in  an  independent  resurvey,  should  be  approached  in  the 
same  way  as  practically  all  problems  in  fragmentary  subdivision, 
though  the  independent  resurvey  may  at  times  involve  the  re-sub- 
division of  a  group  of  many  townships  wherein  ail  conditions,  except 
perhaps  with  relation  to  the  tract  segregation  surveys,  may  be 
comparatively  regular.     First  attention  will  be  given  to  completing 
the  new  township  exteriors  which  are  to  be  independently  resur- 
veyed  after  having  reestablished  the  outboundaries  of  the  group  on 
the  dependent  plan.     The  new  exteriors  will  be  carried  forward  and 
completed  in  harmony  with  the  rules  set  forth  in  Chapter  III  for 
the  establishment  of  original  surveys.     The  new  section  lines  will 
be  run  out  and  marked  as  in  regular  or  fragmentary  subdivision  as 
the  situation  may  be  and  new  meander  lines  will  be  run  as  required. 
The  new  exterior  and  subdivisional  lines  will  usually  be  extended 
across  small  blocks  of  tract  segregation  surveys,  noting  connections 
as  previously  stated,  and  in  such  cases  the  new  lines  and  corners 
will  be  fully  monumented  regardless  of  the  fact  that  some  points 
will  fall  within  the  tract  segregation  surveys.    The  latter  points 
are  required  in  their  usual  function  to  determine  the  subdivision 
of  the  public  lands  affected. 

455.  A  general  exception  to  the  rule  of  extending  the  lines  of 
the  independent  resurvey  across  the  tract  segregations  will  be  made 
in  those  townships  or  portions  thereof  so  densely  covered  by  private 
claims  that  the  remaining  parcels  of  public  lands  may  be  as  well  or 
better  identified  and  described  for  expediency  with  reference  to 
isolated  tract  numbers.     In  such  cases  closing  corners  will  be  re- 
quired on  the  regular  lines  when  entering  or  leaving  public  land. 
The  regular  lines  may  or  may  not  be  extended  as  blank  lines  across 
the  tract  segregations,  according  to  the  plan  of  running  the  new 
section  lines  of  the  resurvey.     Where  this  method  is  employed  it 
will  be  necessary  to  assign  tract  numbers  to  the  vacant  parcels  of 
public  land  and  to  mark  the  angle  points  thereof  accordingly.    Where 
a  parcel  of  vacant  public  land  is  to  be  identified  on  this  plan,  such 
vacant  tracts  will  be  surveyed  by  metes  and  bounds  in  accordance 
with  the  usual  rules.     Rare  cases  may  arise  where  it  will  be  deemed 
expedient  to  segregate  by  metes-and-bounds  survey  certain  quarter- 


RESURVEYS.  306 

quarter  sections  of  vacant  lands  in  accordance  with  the  system  of 
the  original  survey  as  indicated  by  adjoining  tract  segregations  for 
the  purpose  of  affording  a  better  basis  of  disposal  or  for  amendment 
of  entries.  Such  segregations  will  hot  be  made  unless  it  is  con- 
clusively shown  by  the  surveyor  that  the  fractional  lots  and  regular 
quarter-quarter  sections  of  the  resurvey  are  inadequate  as  a  basis 
of  disposal  under  existing  conditions  of  occupancy  on  the  part  of 
settlers  or  of  entrymen  who  may  propose  to  amend.  The  special 
instructions  will  be  made  as  explicit  as  possible  in  these  details, 
which  will  be  determined  upon  when  the  plan  of  the  resurvey  is 
under  consideration  by  the  supervising  officer. 

456.  Where  a  section  of  the  resurvey  is  invaded  by  patented 
tract  segregations,  but  not  by  unpatented  entries  or  selections,  the 
lotting  of  the  public  lands  will  be  carried  out  in  accordance  with 
the  usual  plan  of  lotting  within  fractional  sections  as  outlined  in 
Chapter  III.    The  numbering  of  the  fractional  lots  will  begin  with 
the  number  next  higher  than  the  highest  number  employed  in  the 
section  of  the  original  survey  which  bears  the  same  township, 
range  and  section  number.     This  plan  is  intended  to  avoid  any 
possible  confusion  which  might  arise  from  a  duplication  in  the  use 
of  the  same  lot  numbers. 

457.  A  departure  from  the  usual  rule  for  lotting  is  necessary  in 
order  to  provide  suitable  descriptions  within  unpatented  entries  and 
selections  where  such  tract  segregations  may  be  subject  to  relin- 
quishment  or  cancellation,  also  in  other  cases,  to  facilitate  a  subdi- 
vision of  isolated  tracts  of  public  lands  surveyed  by  metes  and 
bounds.    Two  methods  have  been  found  available,  each  one  better 
suited  to  particular  situations.     Neither  method  involves  any  change 
in  the  instructions  for  the  field  procedure  heretofore  laid  down.    The 
discussion  of  the  merits  of  the  two  methods  and  the  examples  of 
their  use  are  better  adapted  to  the  text  of  Chapter  IX,  where  the 
subject  will  be  found  in  connection  with  other  details  to  be  shown 
upon  the  resurvey  plats. 

458.  The  general  requirements  of  Chapters  II,  III   and  IV  will 
be  fully  observed  in  every  respect  throughout  the  execution  of  the 
independent  resurvey  and  in  the  technical  record  thereof.    General 
titles  (in  addition  to  the  regular  page  heading)  will  be  inserted  in 
the  field  notes  to  indicate  clearly  the  character  of  the  independent 
resurvey,  the  technical  record  of  which  follows;  such  titles  will  be 


306  MANUAL  OF  SURVEYING  INSTRUCTIONS. 

inserted  in  the  body  of  the  field  notes,  as  appropriate,  and  will  show 
the  full  significance  of  all  lines;  as  for  example: 

(a)  "  Metes-and-bounds  survey  of  private  claims  as  originally  lo- 
cated in  accordance  with  the 'survey  executed  by  John  B.  Smith, 
U.  S.  Surveyor,  in  1842;"  and 

(b)  "  Independent  resurvey,  superseding  the  survey  executed  by 
John  B.  Smith,  U.  S.  Surveyor,  in  1842." 

459.  All  monuments  of  the  original  survey,  not  otherwise  re- 
ported upon,  when  traces  thereof  have  been  found,  will  be  con- 
nected by  course  and  distance  with  a  corner  of  the  resurvey,  and 
such  connection  and  a  description  of  the  traces  of  the  original  corner 
as  identified  will  be  recorded  in  the  field  notes  of  the  resurvey.     A 
useless  monument  will  be  destroyed  after  the  point  is  found  to  be 
no  longer  needed  for  the  survey  of  a  claim  of  any  kind  whose  loca- 
tion may  in  any  way  depend  upon  such  monument.     (See  sec.  163, 
Chapter  III.) 

460.  Further  exemplification  of  the  approved  practices  incident 
to  the  successive  field  steps  and  preparation  of  the  field  notes  and 
resurvey  plats  will  be  found  in  the  chapters  that  follow. 

o 


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